On March 8, the Biden-Harris Administration announced it is proposing to strengthen wastewater discharge standards that apply to coal-fired power plants. The U.S. Environmental Protection Agency (EPA) proposal follows the latest science and applies EPA’s longstanding authority under the Clean Water Act to reduce discharges of toxic metals and other pollutants from these power plants into lakes, streams, and other waterbodies. The proposed rule would help protect our nation’s vital water resources that support safe drinking water, agriculture, and healthy communities while providing greater certainty for industry.

“Ensuring the health and safety of all people is EPA’s top priority, and this proposed rule represents an ambitious step toward protecting communities from harmful pollution while providing greater certainty for industry,” said EPA Administrator Michael S. Regan. “EPA’s proposed science-based limits will reduce water contamination from coal-fired power plants and help deliver clean air, clean water, and healthy land for all.” 

Coal-fired power plants discharge large volumes of wastewater into waterways such as ponds, lakes, rivers, and streams. The discharges include pollutants such as selenium, mercury, arsenic, nickel, bromide, chloride, and iodide, nutrient pollution, and total dissolved solids. Exposure to these pollutants can harm people and ecosystems through contamination of drinking water sources, recreational waters, and aquatic life.

EPA’s proposed rule would establish more stringent discharge standards for three types of wastewater generated at coal fired power plants: flue gas desulfurization wastewater, bottom ash transport water, and combustion residual leachate. The proposed rule also addresses wastewater produced by coal fired power plants that is stored in surface impoundments (for example, ash ponds). The proposal would define these “legacy” wastewaters and seeks comment on whether to develop more stringent discharge standards for these wastewaters.

EPA is also proposing changes to specific compliance paths for certain “subcategories” of power plants. The Agency's proposal would retain and refresh a compliance path for coal-fired power plants that commit to stop burning coal by 2028. The Agency is issuing a direct final rule and parallel proposal to allow power plants to opt into this compliance path. Additionally, power plants that are in the process of complying with existing regulations and plan to stop burning coal by 2032, would be able to comply with the proposed rule.

EPA estimates that the proposed rule would reduce pollutants discharged through wastewater from coal-fired power plants by approximately 584 million pounds per year. This means that communities across the country would benefit from cleaner and more resilient water resources, especially low-income communities and communities of color that are disproportionately impacted by pollution from coal-fired power plants.

Learn more about the proposed Effluent Limitations Guidelines and Standards for the Steam Electric Power Generating Category and direct final rule, including how to comment or participate in an online public hearing.


Effluent Limitations Guidelines (ELGs) are national industry-specific wastewater regulations based on the performance of demonstrated wastewater treatment technologies (also called “technology-based limits”). They are intended to represent the greatest pollutant reductions that are economically achievable for an entire industry.

Steam electric plants use fossil fuels (such as coal, oil, and natural gas) or nuclear reactions to heat water in boilers, which generates steam. The steam is used to drive turbines connected to electric generators. The plants generate wastewater in the form of chemical pollutants and thermal pollution from their water treatment, power cycle, ash handling and air pollution control systems, as well as from coal piles, yard and floor drainage, and other miscellaneous wastes.

In September 2015, EPA finalized a rule revising the ELGs for the Steam Electric Power Generating category, setting the first federal limits on toxic metals in wastewater that can be discharged from power plants. In August 2020, the Agency finalized a “reconsideration” rule revising the 2015 requirements for FGD wastewater and BA transport water. EPA reviewed the 2020 reconsideration rule in accordance with President Biden’s Executive Order 13990 directing the Agency to review all regulations and policies undertaken by the previous administration and rescind or revise any that do not protect public health and the environment. In July 2021, EPA announced its intent to develop the rulemaking it is proposing today.