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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 Crystal Lake - Melody Pines

Camp Carpenter
Collection Date
08-25-2025
E. Coli per 100 ml
Lake Right Side: 2
Lake Left Side: <1

Crystal Lake -
 Melody Pines

Collection Date:
08-25-2025
E. Coli per 100 ml
Lake Right Side: 6
Lake Left Side: 16

   
Merrimack River - Arms Park

Crystal Lake -
Public Beach

Collection Date
08-25-2025
E. Coli per 100 ml
Lake Right Side: 14
Lake Left Side: 26

Merrimack River -
Arms Park

Collection Date
08-25-2025
E. Coli per 100 ml 
Single Sample: 9

   
Fisher Cat Ramp Chauncy Ave.

Merrimack River -
Fisher Cat Ramp

Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 548​​​

Merrimack River -
Chauncy Ave.

Collection Date
08-25-2025
E. Coli per 100 ml
Upstream: 2
Downstream: 20

   
Piscataquog River - Boat Launch

Merrimack River -
Front Street

Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 5

Piscataquog River -
Boat Launch/Trestle

Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 7

   
Piscataquog River - Upland Street View of the boat ramp at Piscataquog River Park

Piscataquog River -
Upland Street 

Collection Date
08-25-2025
E. Coli per 100 ml
Lake Right Side: 10
Lake Left Side: 7

Piscatoquog River -
Piscataquog River Park
Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 48

   
Pine Island Pond

Pine Island Pond -
Pine Island Park

Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 4

Piscatoquog River -
Bass Island

Collection Date
08-25-2025
E. Coli per 100 ml
Single Sample: 173

   

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