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Stormwater Management
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Discounted Rain Barrels Available to Order through July 16
Climate crisis is intensifying the water cycle, making wet periods wetter and dry periods drier. Using rain barrels to collect water from your roof will conserve municipal water supply and cut household water bills up to 40%. Read on... -
Adopt a Drain, Help the Mystic River Watershed
Through Lexington’s Adopt-a-Drain program, residents can volunteer to care for a local storm drain and check on it before and after heavy rain, wind, or snow. Read on...
Stormwater 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.
- What Is Lexington Doing About Stormwater?
- What Can I Do About Stormwater?
- Examples of Past Stormwater Projects
IDDE Program
(Updated April 19, 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.
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 community 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
Regulations
A number of federal, state, and local regulations address stormwater issues in Lexington, including:
- The Town of Lexington's Stormwater By-law
- The Town of Lexington Stormwater Regulations (updated June, 2022) (PDF)
- The National Pollutant Discharge Elimination System (NDPES) permit program, authorized by the federal Clean Water Act
- The Massachusetts Wetlands Protection Act
- The Town of Lexington's Wetlands Protection Code
- The State of Massachusetts proposed Stormwater Management Regulations
Stream 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.
Watershed 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.

Storm 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.
This all sounds great! I would like to do my part to take care of these valuable resources!
For ideas on how you can reduce the impacts of stormwater, check out the Citizens' Guide to Understanding Stormwater (PDF), or start with these simple steps:
- Eliminate pesticide and fertilizer use in your yard.
- Scoop your pet's poop-pick it up and flush it down the toilet rather than leaving it on the ground.
- Wash you car in a commercial car wash that treats or recycles its wastewater, or wash your car on your yard rather than on your driveway so that the water infiltrates into the ground.
- Don't ever dump anything down a storm drain-storm drains run directly into streams without being treated, so whatever goes into the drain goes into the stream.
- Use rain barrels to collect run-off from your roof to store for later use in watering your garden or lawn.
- Report illegal dumping and illicit discharging into streams and ponds by emailing the Engineering department.
- Report stream flow problems and impaired outfalls by emailing the Engineering department.
- Adopt a drain near you, and protect the Mystic River Watershed.
Remember even small contributions to the care of our streams has large consequences!
Comments can be submitted to:
Engineering Division
c/o Marissa Liggiero
Samuel Hadley Public Services Building
201 Bedford Street, Room 202
Lexington, MA 02420
Email Marissa Liggiero
Willard Woods Stream Daylighting Restoration Project
What is Stream Daylighting?
Redirecting a stream which was in a culvert, pipe, or a drainage system into an above-ground channel is called daylighting. Typically, the goal is to restore a stream to a more natural state.
Daylighting is intended to improve the riparian environment - the area along the edge of the stream where specific types of plants grow. This area is important to the health of the stream, and to the animals that live in and around the stream.
Why Do This Here?
The existing Willard Woods stone drainage culvert was failing and required replacement. This effort will both accommodate drainage needs but also improve the stream habitat.
The Willard's Woods stream daylighting project was identified as a priority project during Town-wide watershed and stream assessment planning and is a part of Lexington Public Works efforts across the community to enhance drainage systems in an ecological way.
This Project Includes
- Construction of a pedestrian bridge across the "new" stream.
- Construction of a vehicular bridge (for fire access) on the trail to Brent Road.
Read more about the Willard Woods Stream Daylighting Program (PDF).
Vine Brook Bank Stabilization Project
What is Streambank Stabilization?
Streambank stabilization is the practice of strengthening the sides of a stream to reduce the potential for erosion. Streambank erosion is a natural process but in urban environments, it can compromise infrastructure. The goal of streambank stabilization in our community is to restore stable conditions without compromising ecological values whenever possible.
Why Do This Here?
The bank of the Vine Brook at this location is failing and requires stabilization. This effort will accommodate a safe and stable bank slope near our community trail, reduce the potential for sedimentation of the stream, and reestablish streamside vegetation important for Vine Brook ecology.
The Vine Brook bank stabilization project was identified as a priority project during Town-wide stream assessment planning and is a part of Lexington Public Works efforts across the community to enhance drainage systems for flood management, water quality, and overall stream health.
Check out our report from the Vine Brook and Willard's Brook surveys (PDF)