Why Nashua Has Some of the Strictest Environmental Rules in the State

If you live in Nashua or are thinking about moving there, environmental rules are one of those things you probably won't think about until they affect you directly. Nashua has 4 specific rules on the books covering different aspects of environmental rules, and some of them might surprise you.

Erosion 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.

Key details: Governing Code: Chapter 190 Article XXXI — Stormwater Management. Sediment Basin Trigger: 10+ acres disturbed at one time draining to a common point. Sediment Basin Sizing: Runoff from 2-year, 24-hour storm. NHDES AoT Threshold: 100,000 sq ft contiguous (50,000 sq ft in shoreland) — RSA 485-A:17. EPA CGP Threshold: 1 acre disturbance — SWPPP required.

Failure to install or maintain required erosion and sediment controls violates Chapter 190 Article XXXI and is enforceable by stop-work order, denial of permits, withholding of Certificate of Occupancy, and civil penalty under Chapter 190 enforcement provisions. Discharges to waters of the state may be enforced by NHDES under RSA 485-A:22, which authorizes administrative orders and civil penalties. Operating a one-acre construction site without coverage under the EPA Construction General Permit is enforceable by EPA Region 1 with civil penalties up to $59,973 per day per violation under the federal Clean Water Act (40 CFR 19 inflation adjustment). Disturbing more than 100,000 contiguous square feet without an NHDES Alteration of Terrain permit violates RSA 485-A:17 and exposes the operator to administrative and civil penalties.

Compared to other cities, Nashua takes a harder line on erosion control. The enforcement and penalty structure reflects that.

Flood 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.

Key details: Governing Code: Chapter 190 Article VII — Floodplain Development Ordinance. NFIP Effective Date: June 15, 1979 (Nashua joined NFIP). Adopted FIS / FIRM: Hillsborough County, NH — September 25, 2009. Revised Panels: 33011C0514E and 33011C0652E — April 18, 2011. SFHA Zones: A, AO, AE.

Building, filling, or substantially improving a structure inside the Nashua SFHA without a floodplain development permit violates Chapter 190 Article VII and is enforceable by stop-work order, removal order, withholding of Certificate of Occupancy, and civil penalty. Federal consequences are larger: noncompliant structures can jeopardize the city's NFIP eligibility under 44 CFR Part 60, trigger FEMA's Section 1316 denial of flood insurance to the specific property, and disqualify the owner from federal disaster assistance. Insurance carriers may refuse or rate-up coverage on unpermitted floodplain construction. Shoreland violations are separately enforceable by NHDES under RSA 483-B with civil penalties. Substantial-damage and substantial-improvement rebuilds that fail to elevate the lowest floor to or above the base flood elevation violate the NFIP minimum standards.

This is not one of those rules that cities tend to ignore. Nashua actively enforces its flood zones requirements.

Grading & 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).

Key details: Governing Code: Chapter 190 Articles XXVI (Grading) + XXXI (Stormwater) + VII (Floodplain). Soil Removal Permit: Required for loam, clay, sod, sand, gravel (Article XXVI). Soil Removal Exemptions: Buildings, farm ponds, swimming pools, streets, driveways, land contouring. Reviewing Officer: Administrative Officer in consultation with City Engineer. NHDES AoT Threshold: 100,000 sq ft contiguous (50,000 sq ft in shoreland) — RSA 485-A:17.

Removing loam, clay, sod, sand, or gravel without the Article XXVI administrative permit violates Chapter 190 and is enforceable by stop-work order, denial of permits, and civil penalty. Failure to install required drainage facilities or to meet Article XXXI stormwater standards is similarly enforceable, plus may trigger NHDES action under RSA 485-A:22. Discharges that flood neighbors expose the owner to common-law nuisance and trespass liability. Disturbing more than 100,000 contiguous square feet without an NHDES Alteration of Terrain permit violates RSA 485-A:17 with administrative orders and civil penalties. Grading inside a FEMA Special Flood Hazard Area without a floodplain development permit violates Article VII and can jeopardize the city's NFIP standing.

Compared to other cities, Nashua takes a harder line on grading & drainage. The enforcement and penalty structure reflects that.

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).

Key details: Governing Code: Chapter 190 Article XXXI — Stormwater Management. MS4 Permit: EPA 2017 NH Small MS4 General Permit (effective July 1, 2018). MS4 Operator: City of Nashua Division of Public Works. Water Quality Treatment (Water Supply Protection District): 1.0 inch runoff x impervious area. Water Quality Treatment (Other): 0.5 inch runoff x impervious area.

Violations of Article XXXI are enforceable under Chapter 190 of the Nashua Revised Ordinances by stop-work order, denial or revocation of permits, withholding of Certificate of Occupancy, and civil penalty. NHDES may independently enforce violations of the federal Clean Water Act and RSA 485-A through administrative orders and civil penalties under RSA 485-A:22. Knowing discharges of pollutants to waters of the United States without authorization can be prosecuted under the federal Clean Water Act with civil penalties up to $59,973 per day per violation (40 CFR 19, EPA inflation-adjusted). Operating a regulated construction site (one acre or more of disturbance) without coverage under EPA's Construction General Permit (CGP) is independently enforceable by EPA Region 1 and NHDES.

This is one of the stricter rules in Nashua's municipal code. If you are unsure whether your situation complies, it is worth checking with the city before proceeding.

The Bottom Line

Nashua is tougher than many cities when it comes to environmental rules. Out of the 4 rules covered here, 4 are rated strict. If you are a homeowner, renter, or business owner in Nashua, take the time to understand these requirements before they become a problem. Most violations come with fines, and some repeat violations can escalate.

These rules come from Nashua's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.