Water & Sewer

a file



The Water Division is responsible for over 80 miles of various size underground water mains ranging from 2”-16” and is responsible for water services to residential structures and commercial buildings. This division is also responsible for operating and maintaining a radio frequency meter reading system as well as every individual water meter in all residential structures. They are also responsible for accurate retrieval of water meter readings from commercial buildings where the City does not own the water meter. The Water Division is also responsible for the maintenance of approximately 995 fire hydrants and the annual flushing of the water system through fire hydrants.

The Water Division operates numerous regulatory programs in conjunction with the Department of Environmental Protection regulations to ensure quality of water and to protect the potable water system. A synopsis of these programs is as follows:

  • Backflow protection, inspection / device testing / commercial cross connection survey
  • Weekly water sampling and inspection to include testing by the division and testing by the
  • MWRA analytical lab at various locations City wide every single week.
  • Monitoring for lead & copper in the drinking water
  • Annual Leak Detection Program to monitor for unaccounted water
  • Inspection of all water/sewer/drain projects

These bullets are only highlights of the many duties of the Utilities Division.


The Sewer Division is responsible for the operation and maintenance of approximately 78 miles of sewer line and approximately 8,000 residential sewer connections to the sanitary sewer system, as well as the maintenance and operation of approximately 80 miles of storm drain lines which vary in size from 6” in diameter to 72” in diameter as well as maintenance, rebuilding, cleaning of approximately 3,200 storm drains.

The Division works closely with the DEP, EPA and the MWRA in various aspects of regulatory compliance and system monitoring. The division monitors, as well as samples, numerous storm drain discharge points on a regular basis while also sampling and monitoring key junction manholes located within the interior of the storm drain system, as required by the EPA.

System Piping and Statistics

The Water Division serves over 9,200 users with an average supply of over 2.6 million gallons of water every day. Water is supplied by the Massachusetts Water Resources Authority (MWRA). The Town has around 80 miles of water piping running under its streets. The water mains measure from 6 inches to 16 inches in diameter.

Sewage in the City is all gravity fed--there are no sewage pumps stations in the City. Sewage is discharged to the Massachusetts Water Resources Authority sewerage system for treatment at Deer Island Wastewater Treatment Plant.  The sewer mains measure from 6 inches to 24 inches in diameter.

Water and Sewer Billing

The Water and Sewer Division issues bills quarterly, four annual bills per account.

Fiscal Year 2025 Water & Sewer Rates (PDF)

Fiscal Year 2024 Water & Sewer Rates (PDF) 

Fiscal Year 2023 Water & Sewer Rates (PDF)

Fiscal Year 2022 Water & Sewer Rates (PDF)

Fiscal Year 2023 Water & Sewer Rates (PDF)

Watertown - Water and Sewer Rate Study - FINAL 2022 for Fiscal Year 2023

Water System Cross-connection and Backflow Prevention

A cross connection is a connection between a potable drinking water pipe and a non-potable source. For example: you’re planning to spray weed killer on your lawn. You hook up your hose to the faucet on your house and to the sprayer containing the weed killer. If the water pressure drops at the same time you turn on the hose, the pressure change may cause the chemical in the sprayer to be sucked back into your home’s plumbing system through the hose. This is called backflow and could contaminate the water in your home system.

Water utilities deal with this issue on a much larger scale – imagine if your hose were connect to a fire hydrant or a public access faucet (e.g. a campground), then the weed killer would be sucked into the public water supply.

View our flyer (PDF) to learn ways to prevent cross-connection and backflow at your home.

The Massachusetts Plumbing Code (248 CMR 10.00) and the Massachusetts Drinking Water Regulations (310 CMR 22.22) both require installation of backflow preventers at all cross connections. Commercial entities must submit an application (PDF) for approval of backflow devices by DPW.

View our flyer (PDF) for additional information.

The Division continues inspection of commercial backflow prevention devices in compliance with DEP requirements. 

Lead in Drinking Water Information

There is no known lead in the municipal water distribution system.

There are approximately 9,250 water services on record in the City. Review of City records indicate that there are no water services comprised completely of lead pipe.  However, prior to standardizing on copper pipe, water services were often laid using iron pipe.  To create a connection to the water main, short, angled pieces of lead pipe, typically about 2-feet in length, were used.  We refer to these as “goosenecks.” 

Each year, the City removes lead goosenecks as part of the annual road reconstruction projects, water system improvements, and incidental repairs due to service leaks.  Also, projects are required to remove lead services associate with new and significant redevelopment.

Not restricted to Massachusetts or Watertown, some homes internal plumbing may separately have some lead or brass fittings containing lead. For these properties, stagnant water in plumbing fixtures should be flushed prior to use.

For more information, please visit the MWRA website for Lead in Tap Water.  Call the Water Department at 617-972-6420 for information about your service.

Leak Detection Program

Each fall, the Division inspects the water system for leaks. This entails placing microphones on fire hydrants to listen for leaks in the system. 

Canvas “out of service” bags will be placed over hydrant during this process, this is only to protect the microphone.  All hydrants will be in service if needed.

Home Water Leaks

Dripping or trickling faucets and showerheads can waste from 75 to several hundred gallons of water a week depending on the size of the drip. Worn-out washers are the main cause of these leaks and a new one generally costs about 50 cents. A leaky toilet could potentially be wasting 50 gallons of water a day or more due to flapper or flush valves needing to be replaced. These parts are inexpensive and fairly easy to replace. While a leaky faucet is pretty obvious, hidden leaks in the toilet, under the sink, or behind a washing machine can waste a significant amount of water as well as cause damage to your floors or ceilings too. Take a reading of your water meter. Wait an hour, making sure no one uses any water in your home. Check it again. If the reading has changed, you have got at least one leak and you need to investigate. See the Unrepaired Leaks Can Be Costly flyer (PDF).

MWRA Water Conservation Brochure

MWRA How to Find and Fix Leaks

Sanitary Sewer System Backflow Devices

All existing or new building drains from plumbing fixtures liable to backflow from a Department of Public Works (DPW) sewer, or a private sewer connected to DPW sewer, shall be required to have backwater valves installed at the owner’s expense. Any plumbing fixtures located at an elevation below the top of the manhole on the DPW sewer serving the fixture shall be considered to be liable to backflow.

Learn how you can prevent sewer backups on your property (PDF).


The Division also meets the ever increasing reporting requirements of the EPA, DEP and MWRA for drinking water. Annually, the staff performs the six-week program of hydrant and water main flushing (Watertown has nearly 1,000 hydrants and 3,600 catch basins) and conducts weekly drinking water quality sampling, entailing more than 520 samples over the course of the year. The Division inspects and samples river outfalls for quality of the Charles River and continues our program for television inspection of sewer and drain lines, and conducts two annual rounds of sampling for lead in the drinking water.

Hydrant Flushing Schedule

Fall 2023 (PDF)

Spring 2023 (PDF)

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