Environmental Rules in Nashua, NH (2026)
4 verified environmental rules for Nashua, New Hampshire, sourced directly from the municipal code and official government pages.
Verified from official government sources
Stormwater Management
Nashua is a regulated Small MS4 community under EPA's 2017 New Hampshire NPDES Phase II Small MS4 General Permit (NPDES Permit Tracking No. NHR041025; permit became effective July 1, 2018). The city's Stormwater Management Program is codified in Chapter 190 (Land Use), Part 4, Article XXXI (Stormwater Management) of the Nashua Revised Ordinances on eCode360. Engineering review and the NHPDES MS4 program are administered by the Division of Public Works. Discharges drain to the Nashua River, the Merrimack River, Salmon Brook, and Pennichuck Brook (the city's drinking-water source watershed, served by Pennichuck Water Works).
Stormwater Management in Nashua
Heavy RestrictionsErosion Control
Erosion and sedimentation control on Nashua construction sites is regulated under Chapter 190 (Land Use), Part 4, Article XXXI (Stormwater Management) and is layered with NHDES Alteration of Terrain (AoT) permitting under RSA 485-A:17 and Env-Wq 1500, plus EPA's Construction General Permit (CGP) for sites disturbing one acre or more. Article XXXI requires erosion and sedimentation controls to be properly installed and to prevent impacts during construction and post-construction land disturbance activities. Sites that drain to a common point with 10 or more acres disturbed at one time must provide a temporary or permanent sediment basin sized to store runoff from a 2-year, 24-hour storm.
Erosion and Sediment Control in Nashua
Heavy RestrictionsFlood Zones
Nashua's floodplain regulations are codified in Chapter 190 (Land Use), Part 2, Article VII — the City of Nashua Floodplain Development Ordinance — administered by the Building Safety Department and the Division of Public Works (Waterways). The ordinance applies to all lands designated as Special Flood Hazard Areas (Zones A, AO, and AE) by FEMA's Flood Insurance Study for Hillsborough County, New Hampshire dated September 25, 2009, together with the associated Flood Insurance Rate Maps (FIRM) dated September 25, 2009, including revised panels 33011C0514E and 33011C0652E dated April 18, 2011. Nashua joined the NFIP on June 15, 1979. Principal flood sources are the Nashua River, the Merrimack River, Salmon Brook, and Pennichuck Brook. The May 2006 and May 2007 Mother's Day flood events on the Nashua and Souhegan rivers were benchmark events that drove the post-2009 FIRM update.
Flood Zones in Nashua
Heavy RestrictionsGrading & Drainage
Grading and drainage review in Nashua sits at the intersection of Chapter 190 (Land Use) Article XXVI (Grading and Removal of Soil), Article XXXI (Stormwater Management), Article VII (Floodplain Development), and the New Hampshire State Building Code adopted under RSA 155-A. Loam, clay, sod, sand, and gravel may not be taken from land except after application and issuance of a permit from the Administrative Officer after consultation with the City Engineer. Excavation for buildings, farm ponds, swimming pools, streets, and driveways is exempt from the soil-removal permit. Larger projects require NHDES Alteration of Terrain (AoT) permits under RSA 485-A:17 when disturbance exceeds 100,000 contiguous square feet (or 50,000 square feet in protected shoreland).
Grading and Drainage in Nashua
Heavy RestrictionsLooking for Hillsborough County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Nashua city rules.
Environmental Rules in Hillsborough County →