February 6, 2023

Volume XIII, Number 37

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February 03, 2023

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EPA Issues Stringent Effluent Limitation Guidelines for Steam Electric Power Plants

The final rule, touted by EPA as eliminating environmental impacts and cancer risks, substantively changes longstanding regulations regarding steam electric power plants.

On September 30, the US Environmental Protection Agency (EPA) finalized the Steam Electric Power Effluent Limitation Guidelines. The final rule includes new, more stringent limits on wastewater discharges from steam electric power plants and substantively changes longstanding regulations regarding existing and new steam electric power plants.


The Clean Water Act regulates discharge of all pollutants into the waters of the United States. Section 402 of the Clean Water Act authorizes parties to discharge pollutants into the waters of the United States so long as the discharge is pursuant to a National Pollutant Discharge Elimination System (NPDES) permit. Dischargers are required to comply with the effluent limitations in their NPDES permits. The Clean Water Act authorizes EPA to establish both technology based and water quality-based effluent limitations for EPA (or states with delegated authority) to use in setting the conditions and limitations in NPDES permits. The Effluent Limitation Guidelines (ELGs) regulate categories of industrial discharges and are based on the degree of control that can be achieved using various levels of pollution control technology. Here (under 40 CFR Part 423), EPA has changed the ELGs for steam electric power plants, which it expects to apply to wastewater discharges from the subject power plants through new conditions in NPDES permits.

Prior to this final rule, the last revision to the Steam Electric Power ELGs was November 19, 1982. Under the 1982 revisions, limits were based on the use of settling ponds to control discharges of suspended solids (as opposed to dissolved metals and nutrients). Since that time, the implementation of advances in air pollution control technology have changed the contaminants in wastewater from fossil fuel-fired steam electric power plants. Therefore, the September 2015 final rule represents a sea change from the 1982 ELGs both in terms of approach and the stringency of the effluent limits.

EPA issued a proposed version of the Steam Electric Power ELGs in June 2013. In the proposed rule, EPA identified four preferred technology options for setting the ELGs that differed in the number of waste streams covered, size of the units controlled, and stringency of controls. In the final rule, EPA considered a total of six options, including four from the proposed rule and two new variations of the proposed options.

The Final Rule

The options EPA selected in the final rule for steam electric power plants establish new, more stringent requirements for most existing and new sources of wastewater discharges associated with flue gas desulfurization, fly ash, bottom ash, flue gas mercury control, and gasification of coal and petroleum coke. The rule creates more stringent effluent limitations on arsenic, mercury, selenium, and nitrogen for flue gas desulfurization waste streams and ash transport water. The rule also puts a limit on total dissolved solids in flue gas desulfurization wastewater and creates a voluntary program incentivizing plants to meet the more stringent voluntary limits by 2023. In addition, the rule establishes zero discharge pollutant limits for existing plants’ flue gas mercury control wastewater, and stringent limits on arsenic, mercury, selenium, and total dissolved solids in coal gasification wastewater. The rule is significantly more stringent for new coal or petroleum coke plants, in particular.

Each plant subject to the new ELGs must comply with the new rule between 2018 and 2023 (depending on when a plant is required to obtain a new NPDES permit). The new rule sets effluent limits equal to existing standards for oil-fired generating units and small generating units (50 megawatts or smaller).

The effective date of the rule will be 60 days after publication in the Federal Register.


EPA touts the benefits of the new rule as eliminating environmental impacts and cancer risks that it estimates amount to $451 to $566 million per year. EPA stated that 134 out of 1,080 steam electric power plants in the United States will have to make new investments to meet the new, more stringent rule. EPA estimates that the annual cost for power plants to comply with the new regulations will be $480 million.

Copyright © 2023 by Morgan, Lewis & Bockius LLP. All Rights Reserved.National Law Review, Volume V, Number 278

About this Author

Duke McCall III, Environmental law attorney, Morgan Lewis

Duke McCall’s practice focuses on environmental law and complex litigation. He represents clients in contribution actions, enforcement proceedings, citizen suits, toxic tort litigation, and regulatory matters, including actions brought under the Comprehensive Environmental Response, Compensation, and Liability Act (Superfund), the Clean Water Act, the Clean Air Act, the Resource Conservation and Recovery Act, and analogous state laws.

Christopher McAullife, Morgan Lewis, Environmental attorney
Of Counsel

Christopher J. McAuliffe counsels clients on obtaining environmental approvals for new development, climate change laws, and compliance with water pollution control and air pollution control requirements. He also advises clients on solid and hazardous waste, site remediation, brownfields, natural resource damages, and environmental cleanup cost recovery matters. Chris brings to his practice experience gained while working as vice president of environmental, litigation, and employment in the law department of a large energy company.

Conrad W. Bolston, Morgan Lewis, Environmental Litigation Attorney

Conrad Bolston focuses his practice on environmental litigation and regulatory compliance. Conrad has assisted clients with federal and state environmental enforcement matters, environmental due diligence efforts, regulatory guidance, internal investigations, and litigation arising under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), the Clean Water Act, the Clean Air Act, the National Environmental Policy Act (NEPA), the Resource Conservation and Recovery Act, and analogous state laws.