While data centers may provide many benefits, these facilities should not be located near homes or other sensitive areas without measures to protect neighborhoods from data center impacts such as noise, air pollution, loss of scenic views, property value loss, light trespass, etc. If you are concerned about a proposed data center then read on for recommendations to preserve your home and quality of life. If you need immediate assistance with a data center proposed anywhere in the USA, contact CEDS at 410-654-3021 or Help@ceds.org. Through our nationwide network of Good Attorneys, engineers, environment experts, and other professionals, we can help ensure that a proposed data center does not receive a zoning change, conditional use, special exception, special use, or other permits-approvals until all potential impacts to you and your neighbors have been fully resolved.

CEDS DATA CENTER NEIGHBORHOOD PROTECTION STRATEGY

Seeking to kill a data center is a very understandable reaction to learning that one of these major facilities has been proposed near your home. Afterall, nothing so effectively prevents impacts like keeping a major facility from being built.

With some major facilities killing the project is reasonable. However, many local elected officials and other decision-makers view data centers as providing substantial economic benefits (see Tax Revenue below) with few of the adverse effects of other industrial uses. Both factors can make decision-makers less inclined to deny approval for a data center. It is for this reason we urge you to first search for what CEDS calls Equitable Solutions – measures that resolve impacts while allowing a beneficial project to be approved. Potential Equitable Solutions for data center neighborhood impacts are offered in this webpage.

From having helped win many major facility battles, CEDS has learned success in convincing decision-makers to support your position, whether it be nixing a data center or requiring approval conditions that resolve concerns, is frequently 70% a demonstration of substantial community concern, 15% facts supporting those concerns, and 15% showing the facts prove a required finding to grant a key permit or approval cannot be legally granted. Put another way, most decision-makers are far more likely to protect neighborhoods from poorly-planned major facilities when there is widespread support among area residents for a position based on concerns that have a solid factual basis and when those facts directly relate to findings required to grant permits and other approvals. This CEDS basic strategy is allowing neighborhood residents to win a far larger percentage of cases at a fraction of the cost when compared to the conventional approach of relying solely on an attorney and expert witness to block a key permit or other approval. However, both an attorney and experts may be needed to augment the CEDS strategy. The effectiveness of both can be increased with the recommendations presented at the CEDS Smart Legal Strategies webpage.

The first strategy step is to verify that a proposed data center is likely to cause negative impacts to you and your neighbors.

Here’s an example.

Noise may be the data center impact that has the most substantial negative effect on area residents. A noise impact may be more likely if the data center is cooled with air and rooftop fans or if it is likely diesel generators frequently run as a backup power supply. As noted below, noise has caused considerable adverse effects to those living 1,300 feet or more from a data center. But if a proposed data center will use water for cooling and diesel generators are either not proposed or will be within a heavily-sound-proofed building, then noise may not be an issue. However, you must confirm this with the steps recommended in the section of this webpage headed Ensuring Accurate Impact Assessments & Long-term Protection.

Similar guidance for assessing other potential impacts is provided in this webpage along with a description of conditions affecting impact severity as well as possible measures to resolve the impact. For a number of impacts it is recommended that an assessment by specialized professionals be conducted to prove that proposed impact resolution measures will fully protect you and your neighbors. Again, further advice on this point is provided in the section of this webpage headed Ensuring Accurate Impact Assessments & Long-term Protection.

HOW CEDS CAN HELP

If you would like to get a sense whether a proposed data center will harm you or your neighbors, contact CEDS at 410-654-3021 or Help@ceds.org. For no cost we can take a quick look at the proposed site and the proximity to your home to get a sense of potential impacts. We can also try to answer specific questions. However, it is likely that the answer to your questions will be: We need to do research before an answer can be provided. That research, which we call a strategy analysis, can include:

• Verify potential data center impacts and possible solutions to each,
• Determine the permits and other approvals the applicant-developer must obtain and when hearings or other decision points will occur,
• Review the required findings for each permit-approval to determine if the authority exists to deny approval (assuming impacts are substantial and cannot be resolved) or to add conditions to approval resolving your concerns,
• Compile the science-based facts demonstrating that impacts are likely and that key required findings cannot be met,
• Discuss the results of the preceding research with one or more of our Good Attorneys in your state to confirm our lay legal interpretations and get a sense of the likelihood of success,
• Assist you in mobilizing the demonstration of widespread public support essential to convincing elected officials and other decision-makers to support your position,
• Help you find no-cost/low-cost experts to testify as to the validity of impacts and required finding conflicts, and
• Suggest testimony to be presented by you and your neighbors at hearings.

CEDS can provide these services and frequently more for just a few thousand dollars, which is a fraction of what you might pay an attorney or consultant.

WHAT IS A DATA CENTER?

Wikipedia describes a data center as:

“a building, a dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and storage systems.”

The online resource Data Center Map shows that these facilities are present in all 50 states with more than 4,000 nationwide. One source indicates the number of data centers worldwide could increase by 20% annually until 2030.

A typical data center has an area of a million square feet (24 acres) but can be ten times as large. The site on which a data center building is located may range from 30- to 300-acres. A data center may be a single-story building 30-feet tall or, increasingly, a multistory structure.

A data center can be a stand-alone building or located in a campus-like setting (of several to many thousands of acres) with many other data center buildings nearby which may be called a data center alley.

According to the December 2024, report Data Centers in Virginia, these facilities tend to be attracted to:

• States offering sales or business personal property tax exemptions, and
• Sites that are:
  • Near a 230 kilovolt (kV) transmission line, though a 115 kV line could be upgraded to 230 kV,
  • Large,
  • Flat, and
  • Near data center customers and population centers though “rural localities may be able to compete for data centers running certain artificial intelligence (AI) workloads, such as training.”

HOW LIKELY ARE DATA CENTER NEIGHBORHOOD IMPACTS?

Based upon the following, it appears that perhaps one in ten data centers significantly affects those living nearby. This may change though if data centers continue to proliferate, as anticipated, and new, larger facilities crowd into densely populated areas.

Visits To Existing Data Centers

As a first step towards answering the question above, CEDS visited more than two dozen existing data centers in Delaware, Maryland, and Virginia. We had a number of discussions with neighborhood activists fighting to stop data center noise and other impacts. We also reviewing many documents posted online regarding these struggles. From this research it is clear that some data centers cause severe impacts to those living nearby.

None of the data centers visited, however, were causing noise, diesel pollution, unsightly views, or other obvious impacts likely to affect nearby residents. This was true even for the few data centers where there is solid proof that adverse effects have and are still occurring. So, caution is urged in drawing conclusions about potential data center impacts based on a brief visit to existing facilities. This is why CEDS conducted the survey described in the next section of those living near data centers located throughout the U.S.

Though data centers may presently cause minimal adverse effect to area residents, they all likely contribute to increased power generation from coal and other polluting sources. It is unclear though whether the apparently benign data centers will remain so for years to come. It is certainly possible that for short periods, such as during line power outages, diesel generators may run for hours or longer and emit noise or pollution degrading neighborhood quality of life.

Initial Survey of Existing Data Center Neighbors

In addition to data center visits and discussions, CEDS conducted a survey of those living near 33 data centers in 25 states. The survey consists of a letter mailed to 236 households located 20- to 1300-feet from existing data center buildings. Recipients were asked to complete a brief online questionnaire about benefits or negative effects they have experience due to a nearby data center.

This survey was an attempt to get an initial sense for the percentage of existing data centers that cause an adverse effect to nearby residents. However, it was by no means an exhaustive, scientifically valid study. Thus far those living near six (18%) of the 33 data centers reported adverse effects and one reported that a nearby data center was beneficial.

A fact that did emerge from the use of online mapping tools to generate the survey mailing list: the vast majority of the 4,000+ data centers in the 50 states are far from homes and most are in industrial areas. However, as available industrial area sites diminish, future data center locations may move ever closer to homes.

Data Centers in Virginia

Virginia has more data centers than any other of the 50 states. In December 2024, the Virginia legislature released the report Data Centers in Virginia. The 156 page report contained considerable information regarding the pros and cons of data centers as well as recommendations for gaining more of the benefits with fewer adverse effects to those living near and far.

With regard to likelihood of impacts, the report noted that 10% of data centers “appear to have generated noise that nearby residents regard as problematic, according to resident groups and government records.” There is a trend towards taller, larger (million square feet or greater), and more power-intensive data centers which could increase the need for highly effective impact prevention measures to safeguard homes within a thousand feet or so.

In summary, while it presently appears that only 6% to 10% of data centers adversely affect nearby residents, it may take years before the full effects of data centers are known. Therefore, those concerned about a data center proposed near their home should demand the use of the most effective practices presented in this webpage. And because data centers are relatively new and little independent, unbiased research is available, it is likely the measures recommended here will be replaced by more effective safeguards.

SCREENING PROPOSED DATA CENTERS FOR NEIGHBORHOOD IMPACTS?

“Impact” means any aspect of a data center that has the potential to adversely affect area residents. The most likely potential data center impacts are presented in this webpage section. Suggestions are offered for assessing the likelihood of each impact along with measures that could resolve or at least reduce the impact severity of each. Data centers as quality-of-life enhancement opportunities should also be considered with suggestions offered in the section headed Data Centers as Quality of Life Enhancement Opportunities.

The ideal outcome of a data center battle would be measures that fully and reliably resolve impacts while maximizing neighborhood and community-wide benefits. However, if you find that a data center is so poorly-planned that impacts cannot be reduced to a degree most would find reasonable, then demonstrating that you tried to find equitable solutions, but were unsuccessful, will increase the willingness of decision-makers to deny approval.

The word “appear” is used frequently in this webpage because data centers are relatively new with minimal independent study of impacts to nearby residents.

The phrase “decision-maker” refers to local and occasionally state agencies or officials who must grant the permits and other approvals required before a data center can be built. These decision-makers may include a planning commission, a zoning board, a hearing officer, and local elected officials such as a city council, town board, or county supervisors-commissioners. State decision-makers may include an environmental agency though in many parts of the US, once local officials approve a project it is rare that state officials will withhold a permit though impact reduction conditions are common.

Noise

Few U.S. jurisdictions have more or older data centers then Prince William County, VA. The four-minute news clip at the following link, shows the severe impact noise from a data center in Prince William county had on area residents: https://www.youtube.com/watch?v=JflFFqbZ1X8. This and other noisy data centers prompted Prince William County to adopt what may be the best regulations for gaining data center benefits without causing noise impacts to nearby residents. These regulations along with two reports explaining how and why they will safeguard neighbors are posted at: https://app.box.com/s/8bq8gw9uoqjv7xmhtwv49evrq3ecucm2. 

Any jurisdiction that may become home to a data center should adopt a noise ordinance modeled after the Prince William regulations. A good ordinance is not enough. Prince William officials are now in the process of training and equipping regulator staff so they can enforce the noise limits. Few jurisdictions have the financial resources that allows Prince William County to achieve and maintain these noise-enforcement capabilities.

It is far better to require that data centers be designed to be quiet rather then relying on enforcement. At this point it appears that the best way to ensure quiet data centers is to require closed-cycle liquid (water) cooling as opposed to air cooling and to require that backup generators be housed within full acoustic enclosures. This approach avoids a situation where a data center becomes noisy several years after opening and local officials, who have come to rely heavily on data center economic benefits, must chose between enforcing the law against a valued source of tax-revenue and jobs.

Further detail on data center noise follows.

Noise is an unwanted or unpleasant sound. Data center noise is most likely to come from rooftop air-cooling systems and backup diesel generators.

The best way to prevent noise is to design data centers so they do not emit noise and NOT to rely on enforcement.

Here are data center design measures that can prevent noise:

• A data center should be cooled with a closed-loop liquid (water) system or some equally quiet method, preferably not air cooling, and
• If backup generators are proposed, which is usually the case, they must be contained in highly-effective (full acoustic enclosures) sound proofing.

If air-cooling is proposed then the applicant must be required to provide the funds reviewing agencies need to hire an independent noise expert to determine if measures proposed by the applicant will prevent excessive noise in area homes, schools, and other places where we are entitled to peace and quiet.

While considerable noise occurs during the one- to two-years required to construct a data center, the focus here is on noise from a completed data center.

It appears that noise is the data center impact that area residents find most disturbing. Data center noise has been described as a “drone” or “hum”.  The following text is from the 2024 Data Centers in Virginia report:

“Some residents described physical symptoms such as migraines from the facilities’ constant noise. Others said that they experience health problems caused by disrupted sleep, and some residents described an inability to concentrate on tasks. A common theme was poorer quality of life, with some residents avoiding their decks and yards because the sound is louder outdoors.”

There are reports that disturbing noise levels can extend up to 3,000 feet from some data centers and less disturbing noise may be detected as far away as two miles. A portion of data center noise appears to be low frequency which we may not hear but can still affect our health and well-being.

Air Cooling

Data center cooling can be achieved with air or water. Of the two, cooling with water will cause the least, if any, noise impact. If the cooling water is contained within a closed-loop system, which only loses 5% of volume per year, then concerns about impacts to limited water resources should be resolved.

While the initial (capital) cost of air-cooling appears lower then liquid (water) cooling, the long-term costs of air-cooling are higher since it takes more energy (electricity) to cool with air.

It appears that most of air-cooling noise comes from the fans usually located on the roof of a data center building.

In testimony about facilities proposed for Virginia locations, one scientist said that data center noise could be detected up to two miles away. Data center fan noise has been described as a “hum”. The low-frequency (bass) component of data center noise can be very difficult to ignore and block from entering a home. Consider those times when loud bass (low-frequency) music from a passing car stereo passed through the walls and closed windows of your home.

Preventing data center air-cooling noise is difficult to achieve and enforce.

Here’s why.

Below is a slide from a presentation by noise expert David Nelson and JMT at the March 18, 2025 Prince William County, VA Board of Supervisors meeting.

As shown in the presentation slide above, the near universally used noise ordinance measure of dBA (A-weighted decibels) does not capture low-frequency data center noise, which is why C-weighted (dBC) measurement is  also essential. It is very difficult to stop low-frequency noise from entering a home or school, making prevention a crucial step in gaining data center benefits without causing harm.

A common noise ordinance shortcoming is reliance on a single – not to be exceeded noise threshold – such as 55 dBA. To ensure noise is not emitted from data centers three standards may be needed:

• Impulse or one second maximum,
• Intermittent like a train horn blast lasting for several seconds at a time, and
• Constant or Continuous noise.

The slide below contains the DRAFT impulse and intermittent dBA and dBC limits recommended to prevent noise impacts in Prince William County as of March 2025.

However, Prince William County is not focusing on the Octave Band noise criteria shown in the slide below.

Enforcing noise standards is expensive and beyond the capability of many local governments. The last presentation slide below shows the specialized training and expensive equipment needed to enforce the draft standards in Prince William County, which is a wealthy suburban jurisdiction of a half-million people. Even with this County’s ample tax-base, enforcing the standards will not be easy. Many data centers are proposed for far less populous and wealthy jurisdictions. This is why it is vitally important to require that data centers employ highly-effective and reliable noise prevention measures rather than relying on post-construction enforcement of noise restrictions.

Because of enforcement difficulties and the other issues presented above, we urge you to insist on liquid (water) cooling (closed loop) for a proposed data center. Again, with a closed-loop system it may be necessary to replace only 5% of the water used in a year.

If an open loop water-cooling is proposed then insist on an independent assessment of impacts on other water supply users. Without an independent assessment of data center water use impact, others relying on the same source may find the supply no longer sufficient for their needs. Note that some jurisdictions require data center applicants to consider using wastewater for cooling. If a data center is proposed near a sewerline or wastewater treatment plant then this option should be considered with the applicant picking up all costs.

Following is a link to the March 18, 2025 Prince William County Supervisors presentation which begins at 4:04:00: https://pwcgov.granicus.com/player/clip/3614?view_id=23&redirect=true. The 30-minute noise discussion begins at 4:18:00. Viewing the entire 100-minute presentation will give the in-depth understanding of noise impacts key to gaining data center benefits without suffering noise impacts.

Liquid (Water) Cooling

From the perspective of noise impacts to area residents, a liquid-cooled data center is far quieter. The concern with liquid cooling has been the large volume of water consumed. One estimate places the figure at 33 million gallons per year per data center. However, with closed-loop cooling a mere 5% of the water volume need be replaced annually. If both are correct then a closed-loop water cooling system not only resolves noise impacts but excessive water use too. One source indicated that most data centers in parched areas like Arizona are on a closed-loop water cooling system. While the initial (capital) cost of air-cooling appears lower then liquid (water) cooling, the long-term costs of air-cooling are higher since it takes more energy (electricity) to cool with air. In December 2024, Microsoft announced “plans to deploy a zero-water evaporation design in its upcoming data centers.”

Diesel Generators

A data center requires access to reliable power 24/7. A typical data center has 54, trailer-size, one to three megawatt (MW) diesel (occasionally gas) powered generators to serve as an emergency power source. Diesel generators should only operate during a brief, monthly maintenance test and when there is a rare power outage. The monthly tests should take place during the day on a weekday. The following text from the Data Centers in Virginia report provides an indication of how often data center diesel generators may run at times other than monthly maintenance tests:

“…most data center operators interviewed by JLARC staff reported experiencing zero to two minor out ages per site in the last two years, with nearly all outages being only a few hours long.” [Emphasis added because two years may not be representative]

Generators should be fully enclosed within a building that has highly-effective (full acoustical enclosures) sound proofing. If homes, schools, and other sensitive uses are only located on one side of a proposed data center then generators should positioned on the opposite side so the building mass can reduce noise impacts.

Battery backup systems could also serve to minimize the amount of time generators run during an emergency. While solar, wind, and other on-data-center-site clean-energy sources may not be sufficient to meet all power needs, they can recharge batteries that then reduce the duration of diesel generator operation.

Some data centers located in areas where the available electricity is insufficient may run diesel generators more frequently. Since the generators are usually located outside a building, the noise impact can be considerable. It is for this reason that you should insist that a data center only be approved if an independent authority, like the Regional Transmission Organization (RTO), confirms that sufficient power is available so generators will only be needed during a true emergency.

Independent Noise Impact Study Essential

A data center proposal should only be considered after a thorough noise impact analysis has been made available to decision-makers as well as all area residents and other interested parties. The analysis should be conducted by an independent party hired by the decision-making body but paid for by the applicant. The analysis should prove that the data center will not cause noise levels that exceed applicable standards at the data center property line. Noise is measured in decibels (dB); specifically, A-weighted decibels or dBA. Low-frequency (bass) noise is measured in C-weighted decibels or dBC. The independent study should address both A- and C-weighted noise impacts.

Residential noise standards vary throughout the U.S. and may range from:

• No more than 45 to 55 dBA at night, and
• 55 to 60 dBA during the day.

The lower decibel limits are most applicable when a data center is near homes, a school, hospital, or other sensitive land uses. At some highly sensitive land uses such a school or a hospital a limit of 35 dBA may be warranted. For further background see the CEDS How to Stop Disturbing Noise webpage.

Visual Impact

Below are photos of an existing data center built next to a neighborhood. The close proximity of the data center building behind the two homes and poor screening maximize data center visual impact to those residing in the homes pictured below and others nearby.

To get a sense of the potential visual impact, consider that one cluster of data centers, termed a “Data Center Alley,” has been described as:

“A sea of power lines, infrastructure and substations”

that looked

“More like a maximum-security prison than the renderings in the developer’s proposal.”

Data center buildings must be located far enough from homes that sufficient space is available for creating highly-effective visual buffers (95% opacity). Some jurisdictions require that data center buildings must be at least 300 feet from residential property lines and other sensitive land uses. While some data centers are single-story, 30-foot-tall buildings, newer facilities are multistory and much taller. The shadow cast by data center buildings must not fall on nearby residential properties.

The photo above shows data center windows at about the same elevation of the second story bedroom windows of the two homes. The residents of these homes would have no way of knowing if someone is looking from these data center windows into their bedrooms. I suspect most of us would be troubled by this prospect of possible privacy invasion. Good visual buffering could also prevent this impact.

A data center visual buffer should consist of dense evergreen trees that grow sufficiently tall to completely screen the building from view. In some cases trees may not grow tall enough, quickly enough to screen a data center from view. In this case trees may need to be planted atop a constructed earth berm, like that pictured below, located within the data center property line. Note that trees and other vegetation are not a very effective noise buffer.

For further detail see the CEDS webpage Scenic Views & Land Development: Preserving Views from Your home & Other Favorite Places. Examples of highly-effective visual buffering can be found in the webpage section headed Measures to Resolve Viewshed Impacts.

Property Value

There appears to be little independent research regarding data center effects on residential property value.

Noise may be the data center impact most likely to lower the value of nearby homes. There are a number of studies documenting the negative effect of noise on residential property value.

If a data center is located close to homes, such as the situation illustrated in the Visual Impact section above, then a negative property value effect could result.

Several studies documented that commercial uses can depress nearby home values but not at a distance. In King County, Washington commercial uses were found to depress residential properties within 300 feet but not beyond 1,000 feet or so. Locating a massive data center within 100- to 200-feet of homes could lower residential property value if the building is poorly screened from view, noise impacts are significant, or data center lights cause glare into homes. If diesel generators operate frequently then the odors and concerns about pollution-emission health impacts could also lower the value of nearby homes.

Air Quality, Neighborhood Health, Greenhouse Gases & Clean Energy

Diesel generator emissions can pose a threat to the health of area residents if they run at times other than during rare emergencies. Diesel exhaust particulates contain over 40 known cancer-causing organic substances.

Neighborhood Health

The Sierra Club report Demanding Better: How growing demand for electricity can drive a cleaner grid, contained the following assessment of the potential health impact of data center backup diesel generators:

“A research effort in Northern Virginia revealed air permits for over 11,100 MW of diesel backup generators in five municipalities alone – more than 7 percent of the entire peak demand of the 13-state PJM region. The effort revealed over 4,500 operational generators, averaging 2.4 MW each. One permitted facility alone housed 245 generators, averaging nearly 3 MW each for a total facility generating capacity of 716 MW, larger than most coal or gas units [plants] operated by utilities. The capacity of diesel generators in the region, just to provide backup capacity to data centers, is equivalent to the peak demand of PacifiCorp, a utility that serves customers across six western states. Adding together the permit conditions for data center backup generators in Northern Virginia suggests that emissions from these facilities alone could double the electric sector’s emissions of oxides of nitrogen (NOx, an ozone precursor) and contribute to between 50-70 premature mortalities each year.” [Emphasis added]

The Sierra Club Demanding Better report recommended the following alternative to diesel generators:

“In many cases, there may be opportunities to require a large portion of these generators to be non-emitting—such as battery storage, as demonstrated in a pilot project in Belgium. Battery storage facilities co-located at large load centers can also provide valuable utility services for balancing and shifting renewable generation, and relieving temporary grid congestion. Replacing these backup generators with on-site battery storage, and then leaning on that storage during high net system demand periods (and not coincidentally, high cost periods), would avoid a concerning new source of air pollution, significantly reduce strain on the electric system, and bolster renewable integration.”

As with noise, consider calling upon decision-makers to require the applicant to first demonstrate that they are making maximum use of battery systems to minimize the need for diesel- or gas-powered generators. Additionally, the applicant should provide the funds for retaining an independent expert to assess the potential health impacts if any diesel generators will serve as a backup power source. Measures such as Tier 4 generators should be required to minimize diesel particulate emissions. For further detail see the CEDS webpage section Diesel Exhaust & Health.

Regional Air Quality

While one source indicates that generating electricity with diesel releases twice the Green House Gases (GHG) of grid power, data centers may cause a much larger increase in GHG by increasing energy production at coal-fired power plants. The tremendous power needs of Virginia data centers have brought about a delay in the retirement of several aging, coal-fired power plants that had been slated for closure.

Clean Energy

There are a large number of clean energy projects stuck in the review-approval process. In the Mid-Atlantic region alone, these projects could provide 258 gigawatts (GW) of electricity. To put this in perspective a GW is enough electricity to power 700,000 homes or 10 to 20 data centers. Some local governments require that a substantial portion of data center electricity come from solar, wind, or other clean-energy sources. Please consider calling upon decision-makers to include this requirement in permits for a proposed data center.

Accelerating approval of clean energy projects could greatly reduce greenhouse gas emissions as well as the many adverse health effects of coal- and gas-fired power plant emissions. The Sierra Club report Demanding Better: How growing demand for electricity can drive a cleaner grid, outlines a strategy for curbing excessive electricity use at data centers and other power-hungry facilities while picking up the pace of the clean energy transition. Please contact the Sierra Club Chapter in your state to learn how you can help.

Excessive Energy Use

A typical data center may use as much electricity as 50,000 homes. It appears there are a number of measures that could substantial reduce data center electricity use. For example, in the June 2024 Capitol Weekly article California must demand higher energy efficiency from data centers the author wrote…

Compared to mechanical hard disk drives…“Semiconductor-based flash storage, already the standard for consumer devices like mobile phones, laptops, and cameras, is up to 17 times more efficient at storing data. It can also use one-tenth of the power and take up to 94 percent less space in data centers than its superannuated predecessors. Most people assume that data centers are entirely based on modern technology. However, in 2024, over 80 percent of digital information still sits in data centers on spinning mechanical hard disk drives (HDDs).  This energy-intensive technology, celebrating its septuagenarian anniversary, requires enormous amounts of power, cooling, and space and fails more often than currently available technology.”

A number of other energy saving measures are presented in documents such as:

• Data Centers: The Ultimate Guide To Data Center Cooling & Energy Optimization,
• Sustainable IT: Ways IT Can Be More Green and Why It Matters, and
• The Environmental Impact of Cloud Computing and the Next-Generation Data Center.

Sensitive Wetlands, Streams & Lakes

A proposed data center may harm aquatic resources through direct impacts such as filling in a wetland, bridging a stream, or removal of the forest, riparian buffer adjoining a waterbody. Indirect impacts, which may be even more harmful, can result from removing upland forest and covering soils with buildings, parking lots, or other impervious surfaces.

A single data center may occupy a site of 40- to 150-acres with a million square feet or more of impervious surfaces. A data center campus or alley could occupy thousands of acres. Without highly-effective mitigation measures the combined effect of forest loss and impervious surfaces can result in a dramatic decline in aquatic resource health. A stream that once teemed with fish may become essentially dead. A wetland that had supported many birds and other wildlife could go nearly silent.

The table below shows the percentages of upland forest, riparian (streamside) forest buffer, and impervious surfaces where aquatic resource health transitions from excellent, good, fair, and poor.

All waters should be managed to achieve at least Good quality for the reasons presented in the CEDS webpage Making Neighborhood Waters Child Safe & Friendly. If an aquatic resource is considered uniquely important or sensitive then the goal should be Excellent quality. Examples of waters where excellent conditions may be essential are those supporting threatened-endangered species, highly sensitive species such as brook trout, estuarine spawning waters, and public water supply sources.

While the applicant may claim that proposed stormwater management and other measures will resolve aquatic resource impacts, this claim must be scrutinized very closely. The stormwater measures should meet the definition presented in the CEDS webpage section headed Highly Effective Best Management Practices (BMPs).

The effectiveness of these measures may be compromised if your area has a high BMP failure rate due to poor design, installation, or maintenance as described in the CEDS webpage section Inspection, Maintenance & Enforcement. For examples of failing aquatic resource protection measures see the CEDS reports on construction site pollution control and stormwater management measures.

The likelihood of BMP failure may be reduced by requiring independent inspections with access to a fund that can be drawn on to correct deficiencies. Data center aquatic resource impacts can also be offset by planting forest or retrofitting existing impervious surfaces with highly-effective BMPs elsewhere in the same watershed. For further detail see the CEDS webpage Protecting Rivers, Lakes, & Wetlands from Land Development Impacts. For an example of a detailed CEDS analysis of aquatic resource impacts see: https://app.box.com/s/620cksyp2840ktzb1xrrpa5b82z67ika.

Water Supply Impacts

All data centers need a cooling system. Cooling by air or water are the most common. A single water-cooled data center may need a half-million gallons per day unless it is a closed loop system where only 5% of the volume is lost per year. Another issue with systems that are not closed loop is the thermal and other pollution impacts of cooling water discharged to a stream or other aquatic resource. The discharged cooling waters may contain anti-fouling chemicals that could have a toxic or other pollutional impact to receiving waters.

Given the noise impact of air-cooling, all data centers should be water cooled with a closed-loop system. If for some reason closed-loop water cooling is rejected then insist on an independent assessment of potential impacts such as:

• If the cooling water source will be an underground aquifer, then will the data center withdrawal cause water levels to drop to a point that other users can no longer obtain enough water? This would be especially critical issue if area homes and other users obtain water from relatively shallow wells.
• If a surface body like a lake, reservoir, river or even a stream will be the data center water source then will the withdrawal exceed the safe or sustainable yield of the water body? Safe or sustainable yield is the amount of water that can be withdrawn without adversely affecting aquatic ecosystems or other water users.
• If a data center will use water from a public system, then will it cause water pressure to drop below that needed for fire suppression and other uses?

Note that some jurisdictions require data center applicants to consider using wastewater for cooling. If a data center is proposed near a sewerline or wastewater treatment plant then this option should be considered with the data center developer covering all associated costs.

Light Trespass & Dark Sky Impacts

It can make sleep difficult and interfere with the enjoyment of your home, yard, and neighborhood if bright lights cause glare that trespasses onto your property and that of your neighbors. Excessively bright, poorly shielded lights can also reduce our ability to enjoy stars and other features of the night sky.

Night sky impact can be prevented by requiring that data center lighting conform to the Five Principles for Responsible Outdoor Lighting from Dark Sky International.

Adhering to these five principles would go a long way towards the prevention of data center light trespass into nearby homes and yards. Below are examples of good and bad lighting. The best is well-shielded so that light is directed downward and only illuminates the area that needs to be lit.

Data center applicants should be required to submit a plan showing proposed lighting and any proposed measures intended to prevent light trespass and dark sky impacts. The Dark Sky Society publication Guidelines for Good Exterior Lighting Plans contains a number of important safeguards such as “Light levels at the property line should not exceed 0.1 footcandles (fc) adjacent to business properties,
and 0.05 fc (the brightest moonlight is 0.01 fc) at residential property boundaries.” A proposed data center lighting plan should show that this and the other 11 Dark Sky Society Guidelines are met. For further details see the CEDS webpage Light Trespass: Preventing Lights from Glaring into Your Home.

Traffic – Probably Not A Data Center Issue

Once a data center is completed, the volume of traffic, both cars and trucks, is relatively small. A typical data center may have 20 to 100 employees-visitors daily.  A data center may generate about one trip per day per 1,000 square feet of floor space which is relatively low when compared to other industrial land uses such as a warehouse-distribution center.

Other Possible Impacts

Here are some of the other ways in which a data center may impact area residents and the larger population:

• A proliferation of data centers could result in widespread electricity shortages. This impact may be prevented if decision-makers require assurance from the Regional Transmission Organization (RTO) that power can be delivered without jeopardizing other users,
• All residents could be forced to pay higher electricity bills if data center developers-owners are not required to pay for new transmission lines or other infrastructure needed to accommodate these facilities. For example, an analysis by Dominion Energy indicated that doubling peak energy capacity largely to accommodate data center proliferation could cause energy bills for all Virginia households to skyrocket 120% by 2039.
• Construction phase traffic, noise, air pollution, and other impacts, or
• A data center could increase the value of nearby land, which would usually be viewed as a good thing. But some may not agree. For example, increasing assessed property value could raise property taxes on those owning nearby land. Low-income or fixed-income owners may find it difficult to pay the higher property taxes and could be forced to move.

Setbacks & Public Notice

Some jurisdictions require that a data center building be located at least 300 feet from residential property lines.

Frederick County, MD is considering:

• To minimize the likelihood of noise impact, data centers should not be located within a 2.5-mile radius of sensitive facilities such as schools, healthcare facilities, etc. ,
• Data centers must be within two miles of existing high voltage electrical transmission lines,
• Notice and an opportunity to participate in decision-making must be given to all those living or owning property within a half mile of a proposed data center, and
• Generators should be required to meet Tier 4 emission standards and the amount of fuel stored on site should be limited.

Fairfax County, VA requires that:

• A data center building must be located at least one mile from a Metro station entrance, and
• If the data center building is located less than 200 feet from an R (residential) district or a property developed with a residential use, it should include changes in building height or other design techniques to provide variation in building mass as viewed from the nearby residential district.

Virginia has more data centers than any other state, many of which are located in the northern counties of Fauquier, Loudoun, and Prince William. The following recommendations are from Northern Virginia HOA & Civic Associations’ Collaborative Data Center Design and Construction Recommendations, which is a joint publication of the HOA Roundtable of Northern Virginia, the Loudoun Coalition of Homeowners and Condominium Associations, and Protect Fauquier:

I. Data centers should be sited as follows:
A. ¼ mile (1300’) from residential, schools & county/city parks
B. ½ mile (2600’) from state parks
C. 1 mile from national parks

Data center proposals meeting A-C, above siting should achieve a minimum 100 ft setback from their property lines.

Data center proposals that do not meet A-C above siting should, prior to submitting site plans, re-configure building footprints to achieve 500 ft setbacks where possible.

V. Noise
A. Enhanced minimum requirement of 50 dba – daytime, 40 dba – nighttime at data center property line if siting and setbacks in item I, above, not met. When recommended siting and setbacks are observed, local noise ordinance limits, not to exceed 60 dba daytime/55 dba nighttime, at data center property line should be followed.

ENSURING ACCURATE IMPACT ASSESSMENTS & LONG-TERM PROTECTION

A data center proposal should only be considered after a thorough analysis of each potential impact has been made available to decision-makers as well as area residents and other interested parties. It is more likely that the assessment will be accurate and unbiased if it is conducted by an independent party hired by the decision-making body using funds provided by the applicant-developer. The analysis should prove that the data center will not cause adverse impacts, such as noise, beyond the data center property line.

It would be prudent not to accept that a proposed data center will be benign because the assessment, even that by an unbiased third party, says so. The assessment must be based on the assumption that everything will be properly designed, installed, and maintained. As illustrated in the section of this webpage above on Sensitive Wetlands, Streams & Lakes, this is not always the case.

To increase the likelihood that a proposed data center will not become a troublesome neighbor, consider asking your local elected officials to require the applicant-developer provide a listing of existing data centers that:

1. Resemble the facility proposed near your home,
2. Employs the same impact mitigation measures proposed to protect you and your neighbors,
3. Were built by the same developer proposing the facility near you, and
4. Will be operated by the same party as that which will take over the building upon completion.

In addition to the data centers on the applicant’s list, there are several online data  bases you cab use to locate other similar facilities. While there may not be individual data centers where all four criteria are met, it should be possible to obtain a list of several, each of which meets one or more of the criteria. Hopefully, each of the four criteria will be met by at least one of the existing data centers.

If the data centers are within driving distance, then consider visiting on a weekend when nearby residents are most likely to be home. Ask the residents about any adverse effects and as well as benefits they have experienced since data center construction was completed.

For data centers located further away consider sending a letter to nearby residents such as that employed by CEDS and posted at: https://ceds.org/wp-content/uploads/2024/12/CEDS-Data-Center-Neighbor-Survey-Letter.pdf. There are a number of online sources you can use to obtain the name and address of those living near a data center.

If you identify conditions that should resolve your data center concerns, then there are several factors to consider:

• Does the local government have the authority to enforce a condition? In some cases, the answer may be no. For example, in some states a local government can only enforce noise standards if they have adopted a noise ordinance. A number of local governments have not adopted noise ordinances.
• If the condition is enforceable then does the local or state government have a reliable system in place for ensuring the condition is designed, installed, and maintained in a way that will protect you and your neighbors for years and decades to come? CEDS has found that a disturbing number of measures – not necessarily specific to data centers – have failed after several years. For examples of failing aquatic resource protection measures see the CEDS reports on construction site pollution control and stormwater management measures.
• An added degree of protection can be afforded you and your neighbors through a separate, legally-binding agreement between you and the data center site current property owner that also binds on future owners. The agreement should give you the right to monitor conditioned measures, to require that escrowed applicant funds be used to hire independent experts to verify condition failure, and to make any necessary repairs. This agreement should be reviewed by an attorney you hire using funds provided by the data center applicant.

DATA CENTERS AS QUALITY OF LIFE ENHANCEMENT OPPORTUNITIES

Local and state elected officials may find the prospect of a data center locating in their jurisdiction very attractive. As illustrated in the next section, the tax revenue from a data center can be a boon to local governments struggling to secure the funds needed to build new schools, modernize emergency services, upgrade water and sewer services, and a host of other public needs.

If a data center is proposed near your neighborhood and you reach the point where you believe you can win the measures needed to resolve potential impacts, then consider calling for items that would enhance neighborhood quality of life such as a park, a community center, school addition, etc. However, you should first verify that projected tax benefits are real especially when balanced against any incentives or other inducements employed to attract a data center developer to your community.

Increased Tax Revenue

Perhaps the following quote from a Midwest mayor best sums up the potential tax benefits of a data center:

“This project could have potentially meant hundreds of millions of dollars in revenue to the city, the school district, the fire district, and the county. The city could have used these funds to build a police station, improve our roads and other infrastructure and improve parks.”

In those rare cases where a local jurisdiction attracts multiple or a hyperscale data center, the tax benefits can be truly impressive as illustrated by the following text from the Urban Land Institute (ULI) report Local Guidelines for Data Center Development:

“Hyperscale data centers are capital-intensive developments that can cost billions to construct—and are filled with high-value equipment and infrastructure. Taxes levied against them can be a windfall for AHJs [Authorities Having Jurisdiction aka local governments]. A case in point: the data center tax base in Loudoun County, the central hub of North Virginia’s Data Center Alley, increased from $15.996 billion in 2023 to $25.627 billion in 2024, constituting 58.5 percent of the municipality’s [county?] total tax revenue. The presence of data centers can also lower the overall tax burden for residents. In Loudoun, the general property tax rate is set at $0.87 per $100 of assessed value; it would be $1.33 (an additional 52 percent) but for the influx of data center developments, according to the county’s executive director of economic development. By 2026, Loudoun County projects it will receive roughly $1.4 billion in tax revenue from the personal property tax it levies on computer equipment alone. This amount constitutes nearly half of Loudoun County’s entire fiscal 2021 budget of $3 billion.”

According to the December 2024, report Data Centers in Virginia state sales and/or business personal property tax exemptions are a key factor influencing data center developer siting decisions.

Verify That Benefit Claims Are Genuine

A 2024 Forbes article, Tax Breaks For Data Centers Bring Few Jobs, called into question claims by some that a data center would create jobs. The Forbes article cited the ProPublica report How a Washington Tax Break for Data Centers Snowballed Into One of the State’s Biggest Corporate Giveaways. Both articles provide a number of factors local decision-makers should consider before approving a proposed data center.

GUIDING DATA CENTERS TO LOWER IMPACT SITES

Zoning and other land use regulations are key to guiding data centers to locations where benefits can be gained without harming neighborhoods.

Local zoning laws list uses allowed within each zoning district. A number of local zoning regulations treat data centers as telecommunication facilities or other relatively benign uses. These traditionally benign uses are permitted in close proximity to homes. Given the potential impacts of data centers they are more akin to industrial facilities.

When data centers are restricted to industrial sites, they are frequently considered light as opposed to heavy industrial. However, a case can be made that data centers are more heavy, than light industrial. A widely accepted definition of light industrial are those uses where impacts do not extend beyond the site boundary. Given that the noise, air pollution, and other data center impacts can extend into nearby residential areas and beyond, they should be classed as heavy industrial.

If data centers are allowed in light industrial or even some commercial zoning districts then an additional permit should be required that triggers a more in depth and open review process. The permit may be called a Special Exception, Conditional Use, or Special Use. These permits usually require:

• Public notice to nearby residents and others via a letter, signs, etc.,
• More detailed impact studies especially noise,
• Required findings that the data center will not harm nearby residents,
• A public hearing, and
• An opportunity to appeal an unfavorable decision to the local elected body (town council, county supervisors, etc.).

The zoning ordinance might also include use standards such as:

• To minimize noise impacts, require closed loop water cooling and diesel generators in heavily sound-proofed enclosures,
• Data center buildings should be at least 300 feet from residential property lines,
• The data center site should have highly-effective (95% opacity) visual buffers that screen not just the building but the security (prison-looking) perimeter fence, substations, and other objectionable features from the view of nearby homes,
• To prevent glare into nearby homes, data center lighting should conform to the Five Principles for Responsible Outdoor Lighting from Dark Sky International,
• To reduce diesel pollution generators should be Tier 4 or possibly Tier 2 generators with selective catalytic reduction systems or, if practical, use of alternative (lower-impact) fuels such as hydrotreated vegetable oil (HVO),
• A portion, though preferably all, of data center electricity is contracted to come from solar, wind, or other clean energy sources. While onsite solar should be considered it can only provide a portion – not all – of the necessary electricity:. Here’s why: 0.13 megawatt (MW) of electricity per solar acre x 48-acre average data center site = 6.2 MW vs. the 20- to 100-MW needed by a data center.
• Onsite battery systems can reduce the amount of time diesel generators must run when line voltage is insufficient,
• Data centers should meet environmental management standards such as the International Organization for Standardization’s (ISO) 14001 standard, and
• Certification by the Regional Transmission Organization (RTO) that sufficient power is available so diesel generators will be rarely needed and only during a true emergency.