EPA extends wastewater compliance deadlines for coal-fired steam power plants
The Environmental Protection Agency (EPA) published a final rule on December 31, 2025, that changes certain requirements for wastewater discharges from coal-fired steam electric power plants. It applies to the deadlines established by the preceding rule finalized in 2024.
The 2025 final rule:
- Extends the submission deadline for the notice of planned participation (NOPP) required for the subcategory of electric generating units (EGUs) seeking to permanently stop coal combustion by December 31, 2034;
- Extends compliance deadlines for zero-discharge limitations that apply to dischargers of flue gas desulfurization (FGD) wastewater, bottom ash (BA) transport water, and combustion residual leachate (CRL);
- Establishes tiered standards for indirect discharges of FGD wastewater, BA transport water, and CRL; and
- Adds provisions that allow facilities to transfer into and out of the subcategory of regulated EGUs that will permanently cease coal combustion by 2034 until December 31, 2034.
Who’s affected?
The final rule impacts EGUs subject to the effluent limitations guidelines and standards for the steam electric power generating point source category (40 CFR Part 423).
What are the new deadlines?
The 2025 final rule delays the NOPP compliance date. It also extends the deadlines for zero-discharge limitations on FGD wastewater, BA transport water, and CRL. These apply to the best available economically achievable (BAT) limitations for direct dischargers and the pretreatment standards for existing sources (PSES) for indirect dischargers.
| Requirement(s) | Previous deadline | New deadline |
|---|---|---|
| December 31, 2025 | December 31, 2031 |
(Direct dischargers)
| No later than December 31, 2029 | No later than December 31, 2034 |
(Indirect dischargers)
| May 9, 2027 | January 1, 2029, or site-specific date for BAT |
What are the other changes?
EPA’s 2025 final rule sets tiered standards for indirect dischargers of FGD wastewater, BA transport water, and CRL:
- The first tier requires indirect dischargers to meet pre-2024 final rule standards by January 1, 2029.
- The second tier:
- Allows indirect dischargers to continue indirectly discharging up to December 31, 2024, if they certify that they’ll convert to become direct dischargers; or
- Requires indirect dischargers to meet the zero-discharge requirements by January 1, 2029, if they choose not to become direct dischargers.
The final rule also adds provisions that enable facilities to transfer into and out of the subcategory of regulated EGUs that will permanently cease coal combustion by 2034 until December 31, 2034. It allows EGUs to switch between complying with the zero-discharge limitations and the requirements that apply to the subcategory.
Key to remember: EPA has delayed certain compliance requirements for coal-fired steam electric power plants that discharge three types of wastewaters.













































