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New Hampshire Statewide Rule

New Hampshire Alteration of Terrain Stormwater Permits

Heavy RestrictionsApplies statewide across New Hampshire (2026)

Key Facts

Statute
RSA 485-A:17
Threshold
100,000 sq ft
Shoreland threshold
50,000 sq ft
Agency
NHDES
Last verified: August 21, 2026Source: New Hampshire General Court

Summary

New Hampshire RSA 485-A:17 requires state Alteration of Terrain (AoT) permits from NHDES for projects disturbing 100,000+ square feet, establishing uniform stormwater management standards above any local stormwater rules.

I. Any person proposing to dredge, excavate, place fill, mine, transport forest products or undertake construction in or on the border of the surface waters of the state, and any person proposing to significantly alter the characteristics of the terrain, in such a manner as to impede the natural runoff or create an unnatural runoff, shall be directly responsible to submit to the department detailed plans concerning such proposal and any additional relevant information requested by the department, at least 30 days prior to undertaking any such activity. The operations shall not be undertaken unless and until the applicant receives a permit from the department.

Source: New Hampshire General CourtView official code

Full Breakdown

Under RSA 485-A:17 and Env-Wq 1500, the NH Department of Environmental Services administers Alteration of Terrain permits for projects disturbing 100,000 square feet or more, or 50,000 square feet within a protected shoreland. Applications require erosion and sediment control plans, post-construction stormwater management, and treatment of water quality volumes. Designs must follow the NH Stormwater Manual. Municipalities may have additional local stormwater ordinances, but cannot weaken state AoT standards. The state framework also coordinates with EPA's MS4 program for regulated municipalities.

Violations & Penalties

Violations carry administrative fines up to $2,000 per day, restoration orders, and stop-work orders. Willful violations may incur criminal penalties.

Frequently Asked Questions

When do I need a state stormwater permit in New Hampshire?
An Alteration of Terrain permit is required for disturbing 100,000 square feet or more, or 50,000 square feet within a protected shoreland. Smaller projects may still face local rules.
What standards govern stormwater design?
Designs must follow the NH Stormwater Manual published by NHDES, addressing water quality treatment, channel protection, groundwater recharge, and peak flow control for the disturbed area.

Sources

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