EPA Proposes PFAS MCL Compliance Extension to 2031 - Two-Year Delay for Water Systems

EPA proposed extending the compliance deadline for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) maximum contaminant levels (MCLs) from April 26, 2029, to April 26, 2031. The proposed federal exemption under Safe Drinking Water Act sections 1416(f) and 1450(a)(1) would apply to water systems that submit a request for the extension.

The current PFOA and PFOS MCLs remain at 4.0 parts per trillion (ppt) each. The proposed rule does not change these levels, only the compliance timeline for water systems that cannot meet the April 2029 deadline.

How This Affects Site Remediation Work

CERCLA and RCRA Corrective Action Sites

The MCL extension proposal does not change cleanup standards at contaminated sites. Federal cleanup programs continue using the 4.0 ppt MCLs as applicable or relevant and appropriate requirements (ARARs) regardless of water system compliance delays. Your groundwater remediation targets and risk assessments must still meet the established MCL values.

Ohio VAP and BUSTR Sites

Ohio’s PFAS groundwater action levels of 70 ppt for PFOA and PFOS remain unchanged. These state standards are more lenient than the federal MCLs and are not affected by the proposed compliance extension. Sites using federal MCLs as cleanup goals would continue targeting 4.0 ppt.

Drinking Water Pathway Analysis

If your site assessment includes evaluation of drinking water impacts, the proposed extension creates a timing consideration. Water systems serving potentially affected areas may have until 2031 to implement treatment, but your pathway analysis should still use the 4.0 ppt MCL as the protective standard.

What This Means in Practice

The proposed extension addresses water system infrastructure and treatment capacity constraints, not the health-based standards themselves. Water systems must demonstrate they cannot meet the 2029 deadline and submit formal requests for the extension.

For environmental consultants, this means continued focus on the 4.0 ppt cleanup levels while recognizing that some nearby water systems may operate under extended compliance timelines. Your remedial action plans and monitoring programs should account for this potential timing difference.

What to Watch

EPA is accepting public comments on the proposed rule, including the exemption mechanisms and specific criteria for qualifying systems. The agency has not specified when the final rule will be published or what documentation water systems must provide to qualify for the extension.

Bottom Line

The proposed MCL compliance extension affects water system operations, not site cleanup standards. Continue using 4.0 ppt PFOA and PFOS MCLs for remediation planning and risk assessment. The extension may affect coordination with local water utilities but does not change your cleanup targets. For current PFAS standards and sampling protocols, see our PFAS guides and standards pages.