On August 31, 2020, the U.S. Environmental Protection Agency (EPA) announced a final rule addressing effluent concentration limits for certain metals in power plant wastewater under the Clean Water Act. The Steam Electric Reconsideration Rule (SERR) changes several aspects of the coal-fired power plant effluent limitations included in the 2015 Effluent Limitations Guidelines and Standards rule, including the limits for two waste streams: flue gas desulfurization (FGD) wastewater and bottom ash (BA) transport water. Among other things, SERR addresses the effluent concentration limits for mercury, arsenic, selenium, nitrate/nitrite as nitrogen, bromide, and total suspended solids in FGD and BA. The final rule also extends compliance deadlines from Dec. 31, 2023, to Dec. 31, 2025, sets different technological requirements from the 2015 rule, revises the voluntary incentives program for FGD wastewater, and creates compliance subcategories for certain high-flow and low-utilization units set to cease coal combustion by 2028. EPA estimates that these changes will reduce annual compliance costs by $140 million.