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EPA Finalizes Municipal Stormwater General Permit Modifications for New Hampshire Communities

Contact Information: 
David Deegan (
(617) 918-1017

BOSTON - The U.S. Environmental Protection Agency (EPA) has finalized targeted modifications to the 2017 Small Municipal Separate Storm Sewer System (MS4) general permit for 46 New Hampshire communities.

The changes reflected in these final permits are limited modifications to permits that are already in effect and being implemented. The modifications provide either enhanced clarity regarding permit terms or greater flexibility in permit implementation. The modifications are based on a years-long mediated settlement negotiation between EPA and multiple petitioners. The modifications will provide municipalities with more tools and flexibilities for permit implementation while also ensuring that water quality is protected, and the goals of the Clean Water Act are met.

“EPA appreciates the hard work and input from stakeholders on this municipal stormwater permit. When fully implemented, the MS4 permit will protect our environment and adhere to the law, while also allowing municipal leaders the flexibility to make strategic decisions about investments that make sense in their communities,” said EPA New England Regional Administrator Dennis Deziel. “Stormwater is the largest contributor of pollutants to impaired rivers, lakes, streams, ponds, and other waters in New Hampshire. The MS4 permit is an important step to reduce the harmful impact of polluted stormwater on local waterbodies.”

The modified permit becomes effective on January 6, 2021. Municipalities and other regulated entities do not need to submit a new “Notice of Intent” (NOI) for continued coverage under the modified permit.

Modifications to the permit include a provision whereby municipalities can seek implementation schedule flexibilities, streamlined reporting and requirements for new development and redevelopment sites, and additional time for meeting post-construction stormwater control milestones. The modifications either clarify language in the already-in-effect General Permits or provide new, targeted flexibilities for certain permit requirements. As such, EPA concludes that for all permittees, including small government jurisdictions, the modifications may result in some cost savings for permittees (should they choose to avail themselves of these flexibilities), but that those savings will not be at the expense of water quality.


The final permit modifications were developed through a multi-year mediation and settlement agreement between EPA and the parties who challenged the underlying 2017 permit, which included municipalities, environmental groups, and other affected stakeholders. EPA then proposed modifications to the 2017 permit and accepted public comments on the proposed permit modifications for 45 days, from April 23, 2020 until June 8, 2020. EPA received 21 comments on the proposal.

Under the authority of the federal Clean Water Act, EPA’s New England Regional Office issues National Pollutant Discharge Elimination System (NPDES) permits in Massachusetts and New Hampshire. MS4 permits are NPDES permits that authorize certain discharges of municipal stormwater to surface waters. EPA issued the Massachusetts Small MS4 General Permit in 2016, and then issued the New Hampshire Small MS4 General Permit in 2017.

After EPA finalized the 2017 MS4 Permit, various parties filed petitions for review, including the National Association of Homebuilders (NAHB), the New Hampshire Home Builders Association, the Center for Regulatory Reasonableness (CRR), and the Conservation Law Foundation (CLF). These petitions were consolidated with a challenge to EPA’s 2016 Massachusetts Small MS4 General Permit in the U.S. Court of Appeals for the District of Columbia Circuit (DC Circuit).

Once consolidated, the cases were entered into the DC Circuit’s mediation program; after more than two years of discussions, the parties negotiated a proposed settlement agreement which was announced Dec. 27, 2019, issued for public comment, and executed by all parties on April 15, 2020. Under the terms of that settlement agreement, EPA committed to proposing the agreed-upon modifications. EPA proposed the modifications on April 23, 2020 and took public comments until June 8, 2020. EPA received and responded to 21 comments. The settlement agreement also required EPA to take final action on the modifications within nine months of the proposal.

More information

Information on the New Hampshire Small Municipal Separate Storm Sewer System (MS4) general permit, and specific documents including the Federal Register notice of availability of the final modification, the final MS4 permit modifications, a Response to Comments, and other supporting materials are available at: . The Federal Register documents will also be posted to: under the following docket number: EPA-R01-OW-2020-0216.  

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