Stormwater Billing

Westford’s Stormwater Management Utility Fee

The Board of Selectmen established a Stormwater Management Utility Fee on September 24, 2019 in accordance with Massachusetts General Laws Chapter 83 Section 16 to meet increasing demands associated with the Town’s stormwater management program.  The generated fees are used to comply with state & federal permit requirements, maintain & replace aging drainage infrastructure, prevent flooding, and to protect our waterbodies & drinking water supply from harmful stormwater pollutants.

Click here for the Town’s Stormwater Management Utility Fee and Credit Policy

Fee Calculation

Stormwater fees are based on property type and the overall amount of impervious surface area that exists on a property.  The tables below summarize how stormwater fees are calculated. Stormwater definitions are provided at the bottom of this page.

Single Family Residential (SFR)

Impervious Area

(square feet)




SFR1: < 2,000 square feet



SFR2: >2,000 to <= 2,900



SFR3: >2,900 to <= 4,100



SFR4: >4,100 to <= 5,500



SFR5: > 5,500 square feet




Non-Single Family Residential (NSFR)

NSFR properties are charged at a rate of $75 per ERU  


Property Look-up Tool with Impervious Surfaces & Fees

Use the link below to view the impervious surface area mapped on your property used to calculate your stormwater fee.

Click here for Stormwater Viewer

Stormwater Bill Adjustment Process

Property owners may apply for a fee adjustment if they believe that there has been an error in the calculation of their fee. Typical adjustment examples include: impervious surface is not on the property and impervious surface doesn't exist or was incorrectly identified.

Click here to view the Town’s bill adjustment process & procedures

Bill adjustment applications may be filled out online or by using this downloadable application form .

Stormwater Management Utility Fee Credit Process

The credit process provides property owners with the opportunity to lower their stormwater fee by implementing certain stormwater improvements on their property known as Best Management Practices (BMPs). Approved BMPs reduce stormwater runoff, improve water quality, and help reduce costs associated with the Town’s stormwater management program.

Click here to view the Town’s credit process & procedures 

Credit applications may be filled out online or by using this downloadable application form.


Stormwater: Stormwater runoff is generated from rain and melting snow that flow over land and does not soak into the ground. The runoff picks up pollutants like trash, chemicals, oils, bacteria, pet waste, and dirt/sediment that can harm our rivers, streams, lakes, and wetlands.

Impervious Surface Area: Surfaces that are impermeable to infiltration of rainfall and melting snow into underlying soils and groundwater. Typical impervious surfaces include: roofs, decks, sidewalks, parking lots, driveways, etc. Gravel surfaces are not included in stormwater fee calculations.

(SFR): Single Family Residential

(NSFR): Non-Single Family Residential

Equivalent Residential Unit (ERU): A uniform unit of measure based on the amount of impervious surface area on the average residential lot. One ERU in Westford is based on 3,500 square feet of impervious surface.

NSFR Fee Calculation: To calculate the stormwater fee for NSFR property, the total impervious surface area in the property will be divided by 3,500 square feet, and rounded up to nearest whole number to determine the number of ERUs. Each ERU in the property will be billed at the rate of $75 per ERU.

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