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1. What is a stormwater utility?

Similar to water and sewer utilities, which allocate costs based on the amount of use, a stormwater utility fee is determined based on the amount of hardened or impervious surface on a given parcel (such as parking lots, driveways, and buildings). Parcels with more impervious surface are subject to a higher fee. A Stormwater Enterprise Fund is a financial best practice that will provide a transparent accounting mechanism for tracking income and expenses.

The Town of Lexington is considering adoption of a stormwater utility fee to distribute costs of managing stormwater runoff more equitably.  

2. What would the stormwater utility pay for?

The Town and their consultants developed a stormwater rate model that accounted for ten years of projected stormwater program expenditures.  The revenue needs are approximately $2.7 Million for Fiscal Year 2025, which is the first year of the proposed stormwater utility.  

The stormwater utility is intended to fully fund the program, including the following capital and operating expenditures: drainage system improvements, compliance with State & Federal regulations, culvert replacement, water quality monitoring, catch basin cleaning, street sweeping, and other drainage system operations (including labor, contractual services, vehicles, and equipment).  

3. How will the fee be calculated?

The Town will use impervious area as their rate structure, with an Equivalent Residential Unit (ERU) as the basis for the stormwater enterprise fee. An impervious area rate structure in which the unit of charge is based on the median amount of impervious area on a single-family residential parcel is a common, court-tested, defensible, and fair stormwater enterprise fee rate structure.  

In Lexington, 1 ERU is 3,290 square feet of impervious area.  

According to an April 2009 fact sheet titled “Funding Stormwater Programs” by the U.S. Environmental Protection Agency (EPA), impervious area is used as the basis for the fee in more than 80 percent of stormwater utilities. The amount of impervious area on a property directly impacts volume and speed by which stormwater flow enters the stormwater conveyance system and reduces the amount of pervious area where stormwater flows could infiltrate the ground. Likewise, increased imperviousness is associated with increased stormwater pollution that enters local waterways. The Town has developed a dataset with the measured impervious area for each parcel within the service area.

4. Can I reduce my fee?

Yes. This is a major advantage of a stormwater fee.  A credit policy is currently being developed, where property owners may receive a reduction in their annual fee based on their contribution to stormwater improvements (such as collecting and treating stormwater onsite or volunteering for certain activities that benefit the Town’s program).

5. Do other towns in Massachusetts have stormwater utilities?

Stormwater utilities have grown in popularity in Massachusetts, starting with Chicopee in 1998 and adding many more in the last 10 years. See the figure of stormwater utilities in New England (adopted through December 2022). The Western Kentucky University Stormwater Utility Survey 2022 summarizes stormwater utilities across the United States.

Some other Massachusetts communities include:

• Ashland
• Bellingham
• Braintree
• Brockton
• Chelmsford
• Dracut
• Reading
• Shrewsbury
• Westford

These are the number of stormwater utilities by state as of December 2022:

• Massachusetts: 20
• Vermont: 6
• Maine: 5
• Connecticut: 1
• New Hampshire and Rhode Island: 0

View the map of communities in New England that have a stormwater utility (as of December 2022)

6. How would Lexington’s Stormwater Management Program benefit me?

As the Town prepares for the impacts of climate change and increasing State and Federal requirements to mitigate stormwater pollution, this program plays an important role in protecting:

• public health
• the environment
• private property
• the local economy

Green infrastructure and nature-based solutions being used in Lexington have many co-benefits beyond water quality and flood control, such as:

• reduction in urban heat island effect
• improved air quality
• enhanced biodiversity
• increased recreational access
• improved aesthetics.

The stormwater management program strategically combines Clean Water Act goals for water quality with the Town’s work to operate the drainage system to reduce flooding and promote stream health. 

Visit the Town’s Stormwater Management page to learn more about the program and how you can do your part to reduce stormwater pollution.

7. What are the fees for Fiscal Year 2025?

A rate model was developed that distributed the annual stormwater revenue requirements by the total rate base (i.e., impervious area eligible to be charged a stormwater fee). The proposed fee structure includes 3 tiers for Single Family Residential (SFR) properties with less than 7,000 square feet of impervious area, based on their individual amount of impervious area (see table to the right).  For non-single family residential (NSFR) properties and SFR with over 7,000 square feet of impervious area, the impervious area on the parcel will be divided by the ERU value to calculate the total number of ERUs on a per parcel basis.  NSFR properties are defined as all multi-family and non-residential (e.g., commercial, industrial, institutional) properties not encompassed by the definition of SFR.  

A detailed analysis and description of the proposed rate structure is provided in the Stormwater Enterprise Fund – Policy and Process Decision Document (April 2022).  Subsequent Select Board meetings have refined the rate structure and fees presented in the April 2022 document.  The current proposed fees are presented below.

All property owners can use this Stormwater Utility Property Viewer to look up the fee calculated for each property in Lexington.

Tier Label	Description
SFR1	IA <= 2,300 sf
SFR2	2,300 sf < IA <= 4,200 sf
SFR3	4,200 sf < IA <= 7,000 sf
SFR CAP	>7,000

Customer Class	FY 25 Rate
SFR1	$93
SFR2	$155
SFR3	$248
SFR CAP	$155 per ERU
NSFR	$155 per ERU

8. What is considered impervious area?

Lexington’s Zoning office defines impervious surface as: “Any surface which reduces or prevents the absorption of stormwater into previously undeveloped land. Examples are buildings, parking lots, driveways, streets, sidewalks, and any areas surfaced with concrete or asphalt.” 

Gravel surfaces compacted by parking or vehicular traffic and swimming pools are also considered impervious, but properly designed and installed porous asphalt pavements and pavers can be considered pervious.

9. Will tax-exempt properties pay?

Yes. Unlike property taxes, there will be a stormwater fee for all properties with impervious area, including municipal, state, federal, and tax-exempt properties.  This is similar to other utilities in Lexington, like electricity, water, and sewer fees. 

The Town will pay their share of the stormwater fee out of the General Fund.  Public roadways will be exempt from the fee.  

Parcels with less than 400 square feet of impervious area will not receive a bill.

10. What if I believe my fee was incorrectly calculated?

Ratepayers have the right to question how their impervious area was calculated, especially in cases where the impervious area has changed since orthoimagery was captured.  There will be an appeals and adjustment process for customers that disagree with the Town’s impervious area measurement or application of credits.