Stormwater Utility

New Stormwater Utility Fee

The Neighborhood Storage Improvement project, which will provide much needed flood relief to thousands of Wilmette residents, will be the single largest public works investment ever made by the Village. The project is estimated to cost $68 million and will require approximately $4 million in annual principal and interest debt repayments. In order to fund the debt service for the project a new revenue source was needed.

What is a Stormwater Utility fee?

A fee based on a property’s impervious surface area that will be used to cover the required debt repayments. Impervious area includes the building footprints, driveways, patios, and the like. Grass, planting beds and swimming pools are not considered impervious area.

Why was a stormwater fee selected?

A stormwater fee has two primary benefits:

  • It is a dependable and stable revenue source
  • It more accurately reflects a property’s impact on the storm sewer system

Click here to view a feasibility report on the stormwater utility.

To view the September 23, 2019 Committee of the Whole presentation about the stormwater utility fee, click here.

How will the fee be assessed?

Residential properties will be placed into one of three tiers based on the property’s impervious surface area.

  • Tier 1: Less than 3,000 sq. ft. of impervious surface area
  • Tier 2: 3,000 to 4,300 sq. ft. of impervious surface area
  • Tier 3: More than 4,300 sq. ft. of impervious surface area

How much will the fee cost me?

Single family households will pay a fee depending on their Tier. This fee will increase over time and the final rates will be based on the actual project costs and the interest rates paid on the debt service. The 2022 annual rates are as follows and will be billed on your quarterly utility bill:

  • Tier 1: $176.25 (billed at $44.06 per quarter)
  • Tier 2: $215 (billed at $53.75 per quarter)
  • Tier 3: $277 (billed at $69.25 per quarter)

To check what tier your property falls into please search for your address in our Community Portal and click on the “Stormwater Bill Estimate”.

The fee for multi-family and non-residential properties will be calculated based on each property’s individual impervious surface area as follows:
(Impervious surface area / 1 ERU)*$155 ERU rate + $60 fixed fee
Example: (14,360 sq. ft. / 3,590 sq. ft.)*$155 + $60 = $680

Equivalent Runoff Unit (ERU) is a unit of impervious surface measurement that represents the impervious surface area of a typical single-family residential parcel. 3,590 square feet = 1 ERU.

Do permeable pavers or other similar surfaces count towards my impervious surface calculation?

As currently measured all surface features (decks, patios, structures, driveways, etc.) are counted as impervious surface in terms of determining what rate tier a single-family property falls into. Surfaces such as driveways and walkways, whether they are made of traditional concrete/asphalt or permeable pavers, cause water runoff and have an impact on the stormwater system. While permeable pavers, and other similar materials, are better than traditional concrete/asphalt in terms of water runoff, they do still have an impact on stormwater (they can’t be equated to grass or other vegetation surfaces). Furthermore, such surfaces require extensive professional care and maintenance in order to be fully effective which cannot be properly examined nor verified by staff. With over 8,000 single-family properties in the Village, it would be logistically impossible for the Village to operate a stormwater utility fee based on impervious surface in which different types of surfaces were treated differently, or on the unique features of more than 8,000 parcels of property.   After extensive work with consultants and examination of many options, the Village Board concluded that a three-tiered fee schedule based on property size was the most practical and reasonable means of fairly apportioning costs.  It also is true that any exemptions or reductions granted to one property results in higher fees paid by all other property owners in order to generate sufficient revenue to pay for the stormwater system and improvements.

How do I contest my Stormwater Utility Fee calculation?  

Please download an adjustment form here and follow the submission instructions found at the bottom of the form.

Can I check the impervious area calculation for my property?

Residents can visit our community map here and look up their address. From there, you can click on the ruler in the upper right hand side of the page and complete various measurements of your home and features. NOTE: Measurements made on this community map may not be exact.

Are there any incentive and/or credit programs offered to residents who want to lessen their stormwater impact on the Village sewer system?

Information on the Village’s incentive program can be found here.

Information on the Village’s credit program can be found here.

When will the fee go into effect?

The fee went into effect on January 1, 2020.



This page was updated on 1/3/2022.