Stormwater Management

Water StreamStormwater management protects our municipal drainage system by guarding against the washout of construction sediment and other foreign material being deposited into our streams. Lexington has three watersheds our stormwater contributes to:

Our stormwater map - GIS Map for Public Use

Stormwater is the water that flows over the ground when it rains or snows. When precipitation falls on vegetated areas, most of the water soaks into the ground rather than running over its surface.

But when precipitation falls on impervious surfaces, such as driveways, sidewalks, and streets, it can't soak into the ground, so it runs over the surface. This run-off either flows directly into a stream or into a storm drain, which eventually discharges into a stream.

As stormwater runs over these manmade surfaces, it picks up pollutants, such as oil, fertilizer, sand, and trash, and carries them with it as it flows into streams. These pollutants can contaminate drinking water supplies, fish and wildlife habitat, and swimming facilities. Stormwater can also cause erosion and flooding problems.

For more information on stormwater, visit the EPA's Stormwater Page.

  1. What Is Lexington Doing About Stormwater?
  2. What Can I Do About Stormwater?
  3. Examples of Past Stormwater Projects

IDDE Program

(Updated October 2, 2023) 

What is going on?

This spring and summer, the Town of Lexington (Town) will be working with Woodard & Curran along with their subcontractor SDE Engineering to perform illicit discharge detection and elimination (IDDE) investigations throughout the Town, including at Lexington High School.

  • Illicit discharges are direct connections or indirect discharges to the stormwater drainage system that are not composed entirely of stormwater, except as exempted in Town of Lexington Municipal Code Chapter 114-3 Stormwater Management. 

Where is this work happening now?

Week of October 2, Weather Permitting: Pleasant Street, Lowell Street, Summer Street, Lexington High School (Outside/Yard), Bow Street, Fottler Avenue, Fletcher Avenue

Why are IDDE investigations performed?

The Town is authorized by the State and EPA to discharge stormwater runoff into local waterways in accordance with the Clean Water Act.  It is our responsibility to meet these conditions and prevent wastewater (sewage) or other illegal substances from entering our stormwater drainage system. 

  • Stormwater drainage systems are used to convey stormwater away from houses, buildings, roads, streets, etc., and generally include series of catch basins, manholes, and underground piping. 
  • Separate piping systems are used to handle stormwater and wastewater (sewer).

To meet this responsibility, we monitor our stormwater discharge points (outfalls and inter-municipal connections to our neighboring towns) for indicators of potential illicit discharges (like sewage) into the Town’s stormwater drainage system. The results of this work have been used to identify areas in the Town that should be targeted for IDDE investigation. 

What should I do if I have questions?

If you have any questions, please do not hesitate to contact me, Marissa Liggiero, at (781) 274-8335.

Rain Barrel Program

In the spring of 2019, Lexington DPW began a new program and combined forces with the Lexington Girl Scouts as part of a commuWhen it Rains You smile, The Great American Rain Barrel  Company nity service program to encourage residents to purchase rain barrels as part of an ongoing conservation program. The program was a success and the Town continues to roll out the program each spring if possible. Rain barrels lower municipal water demands and save energy at water treatment facilities by reducing water pollution and storm water runoff. Using rain barrels to collect water from your roof will conserve municipal water supply and cut household water bills up to 40%. Rain Water is free, has chemicals such as chlorine or fluoride, making it an excellent water source for lawns, plants and gardens.

Lexington has partnered with the Great American Rain Barrel to offer rain barrels. The barrel can be easily attached to your downspout. We post information on this page when the current program details are available.

Stormwater Management Plan


A number of federal, state, and local regulations address stormwater issues in Lexington, including:

Interns Working on StormwaterStream Team Water Sampling Program

The Town of Lexington has been working in partnership with the University of Massachusetts Lowell since 2014. This program involves groups of engineering and environmental science students from the university collecting stream samples in Lexington, testing and tracking the results.

The program has been very successful. You may see these eager faces around town donning their distinctive Stream Team vests and carrying coolers of water bottles.

Stream running through woodsWatershed Stewardship Program

The twenty streams that wind through Lexington play important roles in our community, moving and cleaning water, providing wildlife habitat, creating wetlands, and serving as aesthetically pleasing places to visit.

All of Lexington's streams start within the bounds of Lexington and flow outward to other communities in three major watersheds - the Charles River Watershed, the Shawsheen River Watershed, and the Mystic River Watershed. As they flow through these urban areas, the streams face challenges from stormwater run-off and other factors.

In 2012, the Town Conservation and Engineering departments worked together to establish a Watershed Stewardship Program that enlisted volunteers to survey streams for stormwater-related problems and assist with remediation efforts.

Currently, the Engineering Department runs this program through a partnership with UMass Lowell's Civil Engineering Department. The original Watershed Stewardship Program started in 2012, engaged Conservation Steward volunteers to conduct observational stream surveys on all of Lexington's streams to develop a better understanding of the issues that affect their health and function. Follow-up efforts to these surveys include outreach and education projects, stream clean-ups, and water quality monitoring. Look over the previous content to learn more about the Stormwater run-off.

Volunteer installing a storm drain markerStorm drain markerStorm Drain Markers

The Town, through the stewards, has installed markers on storm drains that read "Don't Dump, Drains to Stream" to increase public awareness that storm drains discharge directly into our streams.

Check out the following resources for more information on storm drain marking:

To volunteer to help install markers on storm drains, email the Engineering Division.

Stormwater Drain