Water Quality

Weekly Water Sample Results

In accordance with New Hampshire RSA 485-A, Class B waters — which are suitable for fishing, swimming, and other recreational uses — should not exceed an average of 88 E. coli per 100 milliliters of water.

If sample results exceed an average of 158 E. coli per 100 milliliters, the Manchester Health Department may close the area to swimming until water quality improves.

Weekly sampling helps the Health Department monitor water quality at natural bathing locations throughout the city.

Current Sample Results


Camp Carpenter Collection Date 06-02-2026 E. Coli per 100 ml Lake Right Side: 5 Lake Left Side: 5	Crystal Lake - Melody Pines Collection Date: 06-02-2026 E. Coli per 100 ml Lake Right Side: 1 Lake Left Side: 1


Crystal Lake - Public Beach Collection Date 06-02-2026 E. Coli per 100 ml Lake Right Side: 30 Lake Left Side: 23	Merrimack River - Arms Park Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 172


Merrimack River - Fisher Cats Launch Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 155	Merrimack River - Chauncy Ave. Collection Date 06-02-2026 E. Coli per 100 ml Upstream: 186 Downstream: 178


Merrimack River - Front Street Collection Date 06-02-2026 E. Coli per 100 ml Single Sample:144	Piscataquog River - Electric Street Boat Launch/Trestle Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 50


Piscataquog River - Upland Street Collection Date 06-02-2026 E. Coli per 100 ml Lake Right Side: 58 Lake Left Side: 42	Piscatoquog River - Piscataquog River Park Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 57


Pine Island Pond - Pine Island Park Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 40	Piscatoquog River - Bass Island Collection Date 06-02-2026 E. Coli per 100 ml Single Sample: 77


Merrimack River - Fisher Cat CSO Collection Date 08-25-2025 E. Coli per 100 ml Single Sample: 649	Merrimack River Amoskeag Falls Marina No longer Testing