Water Department

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Part of South Main Street between Brook Street and Elm Street will be closed Friday, November 11, 2022 for several hours in the morning while the Water Department paves part of the road.

More information from the Water Department can be found below:

FROM: Cohasset Water Department

DATE:  November 10, 2022

SUBJECT: Paving South Main Street 

The Water Department will be paving in the area of 55 South Main Street tomorrow, Friday, November 11th. Police will be onsite rerouting traffic starting at 8:00 a.m. around the downtown area. Work should be complete by 11:00 a.m.

We appreciate your patience while we improve our infrastructure. Should you have any questions please contact the Water Department at (781) 383-0057 between the hours of 7:00 a.m. – 3:30 p.m.


The Cohasset Water Department provides public drinking water to about 7,000 Cohasset residents with about 2,600 connections, 38 miles of water mains, 750 valves, and 400 hydrants.

Water Quality Report
Stay connected with the water quality in Cohasset by viewing the Water Quality Reports.

The Water Department provides water for about 90% of Cohasset (the other 10% receive water services from Aquarion Water Company) and it also provides and maintains a reliable water system for Cohasset's Firefighters.

Our Water Supply

Cohasset's drinking and usable water comes from three water supplies, which are Lily Pond, Aaron River Reservoir, and Ellms Meadow. Lily Pond has a maximum capacity of 79 million gallons of water, which spans over a 52 acre area. Aaron River Reservoir has a maximum capacity of 479 million gallons of water over a 136 acre area. Aaron River is connected to Lily Pond and it is used as a supplement in times of high water demand.

The smallest of the 3 water sources is Ellms Meadow in downtown Cohasset with the pumping station on James Lane.  The wellfield previously provided a seasonal supply of water. Since it was insulated in 2015, the wellfield is now pumping year round as water levels permit.  During peak flow it provides about 30% of Cohasset's usable water.  Since the reservoir was opened in the 1970s, Cohasset's water users have not been affected by seasonal droughts even though the surrounding towns have.

Through a state permit, the water department is selling water on a monthly billing basis, to the Linden Pond complex, which provides annual revenue of approximately $300,000. The water is supplied through an interconnection with the Hingham system that was totally paid for by Linden Ponds. No water is sold or given to Hingham.


  • Manage, improve and control all aspects of the town water system. 
  • Award contracts for work to be performed in the maintenance and construction of Town water systems
  • Establish rules and regulations for the use of the Town water systems
  • Fix just and equitable rates for the use of Cohasset's water system
  • Keeping necessary records
  • Maintain daily flow rates and acceptable water quality
  • Provide on-site inspections and evaluations
  • Submit reports to the Massachusetts Department of Environmental Protection

Lily Pond WTP Capital Improvement Plan Presentation

Lily Pond WTP CIP Presentation

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