Glossary

A permit required under Section 404 of the Clean Water Act before anyone can fill or disturb wetlands. Issued by the Army Corps of Engineers. Requires public notice and a comment period.

An underground layer of rock or sand that holds water, like a natural reservoir beneath your feet. Wells pump water up from aquifers. Heavy pumping in one spot can lower the water level for everyone n...

Diesel generators that provide emergency power during grid outages. A large data center may have dozens, producing nitrogen oxides, particulate matter, and formaldehyde when they run.

A power source connected directly to a facility, bypassing the public grid. Does not go through the utility or the interconnection queue. Think of it as a private pipeline for power.

A land use automatically permitted under the zoning code. If data centers are by-right in industrial zones, the developer does not need a public hearing or special approval.

An auction run by a regional grid operator (like PJM) where power plants bid to be available in future years. Higher demand raises auction prices, which flow through to household electric bills.

The documented record showing who collected a piece of evidence, who handled it, and how it was stored. Without chain of custody, a water sample or noise recording can be challenged as altered or cont...

A provision that lets a community take back tax breaks if the developer does not deliver what it promised—usually a certain number of jobs or level of investment.

A data center where multiple tenants share space and infrastructure. In the behind-the-meter context, it refers to a data center tapping into an existing power plant already counted in grid reliabilit...

A legal defense where the developer argues you moved near the data center knowing it was there. Does not always win, but it is harder to fight if the facility was built before you arrived.

A contract between a developer and the community. The developer commits to specific benefits—cash payments, jobs, environmental protections—in exchange for community support or approval.

A long-range document that guides how a community will grow. It covers land use, transportation, utilities, and open space. Zoning decisions are supposed to follow it.

Special permission required to build something not normally allowed in a zoning district. Requires a public hearing. The governing body can attach conditions or deny the application. Also called a spe...

A dip in the water table around a pumping site. Wells within the cone may produce less water or go dry. If a data center pumps heavily from an aquifer, surrounding wells can be affected.

A state office that represents utility customers in proceedings before the public utility commission. Also called consumer counsel, public counsel, people’s counsel, or ratepayer advocate.

A fee arrangement where your lawyer takes a percentage (typically 33–40%) of any judgment or settlement. You owe nothing if the firm loses.

A sound measurement scale that treats all frequencies equally, unlike dBA which filters low frequencies. Data center hum is low-frequency and may read much louder on dBC than dBA.

A unit measuring sound intensity. Normal conversation is about 60 dB. Data center cooling equipment produces 55 to 85 dB. Backup generators can reach 100 to 110 dB.

Money set aside before construction to pay for removing a facility and restoring the site when the project ends. Common for solar farms and wind turbines. Rare for data centers.

Three players in every data center project. The developer builds the facility and negotiates zoning and tax deals. The tenant (usually a tech giant like Amazon, Google, or Microsoft) runs the servers....

A legal theory measuring property damage by comparing what your property was worth before the data center and what it is worth after. The difference is your damages.

The part of a lawsuit where both sides must share their documents, records, and evidence with each other before trial. It is expensive and time-consuming, but it also forces the other side to reveal w...

The case number and file for a utility rate proceeding at the public utility commission. You need the docket number to file public comments.

The government’s power to take private land for public use, with compensation. Used for roads, utilities, and transmission lines—including lines built to serve data centers.

A detailed analysis of how a proposed project will affect the environment. Required under NEPA for major federal actions. Some states have their own environmental review laws.

Environmental, Social, and Governance ratings that score companies on climate, workers' rights, and honest management. Used by institutional investors to measure risk.

A cooling method where water absorbs heat and evaporates. It is effective but consumes millions of gallons per year. That water is gone — it does not return to the source.

Regulates interstate transmission lines and wholesale electricity markets. Does not regulate data centers directly but oversees the grid that serves them.

A request for government records under the Freedom of Information Act (federal) or your state’s equivalent. Also called a public records request or open records request.

Tax money the government chose not to collect because of a tax break. It is money that would have gone to schools, roads, and services.

When a company makes itself look more environmentally friendly than it actually is—through misleading claims, selective data, or accounting tricks.

A company that builds and operates data centers at massive scale, often measured in gigawatts of power demand. Examples include Amazon (AWS), Microsoft (Azure), Google (Google Cloud), Meta, Oracle, Co...

A court order requiring someone to do or stop doing something. In data center cases, an injunction can force the operator to reduce noise, install sound barriers, or limit operations during certain ho...

The waiting list to connect a new power source or large customer to the electric grid. Wait times average 5 to 10 years.

A special rate structure designed to prevent data centers from shifting grid upgrade costs to residential customers. At least 34 states now have some form of large-load tariff.

A state law requiring environmental review of major projects, modeled on the federal National Environmental Policy Act. About 16 states have some version.

Cutting power to certain customers during grid emergencies. Michigan requires data centers to reduce power before residential customers are affected.

A unit of electrical power. One megawatt can power about 800 homes. A 500-megawatt data center uses as much electricity as a small city.

A contract requirement that a data center pay for a percentage of its reserved power capacity even if it uses less. Michigan requires 80%; Virginia requires 85%.

A temporary pause on new permits or applications. Gives the community time to study impacts and update regulations. Typical duration: 6 to 12 months.

A contract that bars parties from sharing certain information. Developers routinely ask local officials to sign NDAs before revealing project details. NDAs between public entities and private companie...

The federal law that requires agencies to study the environmental effects of major actions before approving them. Does not apply to most private data centers unless federal permits or funding are invo...

A Clean Air Act permit required when a new facility or major modification will emit significant air pollution. Data centers with many diesel generators may trigger NSR.

National Pollutant Discharge Elimination System permit. Required under the Clean Water Act for any discharge of pollutants into waters of the United States.

A legal claim that someone else’s use of their property unreasonably interferes with your use of yours. The most common legal tool for neighbors affected by data center noise or light.

A state law requiring government bodies to conduct business in public. Votes taken in secret may be void. If your governing body discussed a data center deal in closed session, check whether that sess...

A law passed by a local government—a city council, county board, or township. It works just like a state or federal law, but only within that jurisdiction.

An additional layer of zoning rules applied on top of existing zoning in a specific area. Can add requirements like larger setbacks, noise limits, or conditional use review for data centers.

Divide the total value of tax breaks by the number of permanent jobs to calculate the public cost per job. Data centers typically cost $200,000 to $965,000 per permanent job in subsidies — far above t...

A fixed annual payment a company makes instead of regular property taxes. Usually much lower than the full tax bill, but it ensures schools and services get something rather than nothing.

The regional grid operator for 13 states and D.C., serving 65 million people. Manages the transmission grid and runs capacity auctions.

A group of appointed local residents who review building and land-use proposals. They hold public hearings and recommend whether the elected board should approve or deny a project.

A ratio measuring data center electricity efficiency. A PUE of 1.3 means that for every watt powering servers, another 0.3 watts goes to cooling and overhead.

A court decision that future courts are expected to follow in similar cases. The first big ruling on data center noise will shape every case that comes after it.

A water rights system used in most western states. The rule is "first in time, first in right." Senior water rights holders get their full share before junior holders get any.

Investment firms that pool money from wealthy investors and pension funds to buy and run companies. They are not traded on the stock market and disclose far less than public companies.

A state agency that regulates electric, gas, and water utilities. Sets the rates your utility can charge. Also called a public service commission (PSC) in some states.

A network of community-owned air quality sensors that measure fine particulate pollution (PM2.5). Sensors cost about $240 and upload data to a public map.

The total value of a utility’s assets on which it is allowed to earn a return. When a utility builds infrastructure to serve data centers, the cost goes into the rate base and is spread across all cus...

A proceeding at the public utility commission where a utility requests permission to change the rates it charges. The public can file comments and testify.

Anyone who pays an electric or water bill. When a utility spends money on grid upgrades, ratepayers are the ones who cover the cost through higher bills.

A vote by the public on a specific question, such as whether to overturn a zoning decision. Rules vary by state.

A paper credit representing one megawatt-hour of electricity from renewable sources. Companies buy RECs to claim their electricity is "green," but the certificate may not correspond to power the compa...

Changing the zoning classification of a piece of land—for example, from agricultural to industrial. Usually requires a public hearing and a vote.

A water rights system used in most eastern states. Landowners next to a body of water have the right to use it in "reasonable" amounts. If a data center’s withdrawals impair your use, you may have a l...

The required distance between a building and the property line, road, or other boundary. Standard industrial setbacks (50 feet) were not designed for data centers. Communities have required 300 to 1,5...

A business that exists only on paper, used to hide who really owns a project. Developers set up LLCs with names like "Maple Leaf Holdings" so their real name does not appear in county records.

A detailed review of a proposed development's layout, including building placement, parking, landscaping, and drainage. Required for most commercial and industrial projects.

Strategic Lawsuit Against Public Participation. A lawsuit filed by a developer to silence opposition. Most states have anti-SLAPP laws protecting public hearing testimony and advocacy.

The legal right to bring a case or participate in a proceeding. You usually have standing if a decision directly affects you—for example, you live near the project site.

Money or tax breaks that the government gives to a company to attract it to an area. The cost is covered by other taxpayers—through higher taxes or fewer services.

An expiration date built into a law or agreement. Without one, a tax break can last decades longer than anyone intended.

An independent bond held by a bonding company — not by the developer — ensuring financial guarantees survive even if the developer goes bankrupt.

A government action that deprives a property owner of the use or value of their property. If a moratorium eliminates all economic use of the land, it may be challenged as a taking. The Supreme Court h...

A deal where the government reduces or eliminates a company’s taxes for a set number of years. Abatements can apply to property taxes, sales taxes on equipment, or both. The lost revenue has to be mad...

Tax Increment Financing. A tool that diverts future property tax growth in a designated area to pay for infrastructure improvements. Can be used to fund data center infrastructure at taxpayer expense.

A legal term for a wrongful act that harms someone, which the harmed person can sue over. Nobody goes to jail—but the person or company responsible may have to pay money for the damage.

An exception to the zoning rules granted to a specific property owner. Requires a showing of hardship.

A developer's claim that they should be judged under the rules that existed when they applied, not new rules adopted later.

The set of local laws that controls what can be built where. Divides land into zones (residential, commercial, industrial, agricultural) and lists the uses allowed in each.

A change to the zoning code itself—for example, adding a definition of "data center" or moving data centers from by-right to conditional use. Requires a public hearing and a vote.