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Stormwater Utility

Utility Update- December, 2015

Since 2011, the Village of Winnetka has been developing a Stormwater Management Program, outlining millions in capital improvements designed to deliver long-term flood relief from structural flooding in large scale storm events.  A number of these infrastructure projects, totaling $10,654,008, have now been brought to fruition, including Northeast Winnetka (Lloyd Outlet and Tower Relief Sewer), Winnetka Avenue Pump Station, Northwest Winnetka (Greenwood and Forest Glen), and Ash Street Pump Station.  Another portion of the Management Program was the preliminary design and engineering of the Willow Road Stormwater Tunnel and Area Drainage Improvements (STADI) project.  In September, the Village Council suspended further work on the STADI project due to significant cost increases from earlier project estimates.

After extensive study in 2013 and 2014, the Village approved a stormwater utility fee—finding it to be an equitable method to pay for planned stormwater improvements, because it is based on each’s property’s impervious surface and its impact upon the stormwater system.  Since every property contributes stormwater, every property owner helps to pay for the flooding solutions.  Stormwater utilities have become more common throughout the State, as they provide a predictable and sustainable funding source to maintain and improve a stormwater system. 

The Village began billing property owners for stormwater utility service effective July 1, 2014, based on the amount of impervious surface on the property.  Impervious surface is calculated as an Equivalent Runoff Unit, or ERU; one ERU equals 3,400 square feet of impervious surface.  The fee appears on each customer’s regular utility bill, along with Village fees for water, electric, sanitary sewer, etc.  Winnetka’s stormwater utility is a set fee: $21.83 per ERU, per month, with most residential customers billed bi-monthly.

The following chart displays the types of impervious areas considered in Village calculations.Impervious_Surfaces

It is important to keep in mind that the current rate of the utility fee is structured based on two components: 1) annual, ongoing storm sewer system operation and maintenance (O&M) costs and 2) required principal and interest payments on general obligation debt issued by the Village to fund stormwater projects.  In late 2013 and early 2014, the Village issued $16.5 million in general obligation bonds to be repaid over a 30-year period—allowing assets to be paid for over the life in which they are used.   The current rate of the utility reflects the costs and investments made to the Stormwater Management Program to-date.

While the STADI project has been suspended as the Village pursues an evaluation and exploration of non-tunnel alternatives for flood relief in western and southwestern Winnetka, completion of flood relief projects continues, as do O&M needs.  Additionally, the Village has been using the bonds to pay for current flood relief projects and will continue to pay the principal and interest on the previously issued debt.  Until there is consensus on alternative stormwater improvements that can provide flood mitigation, it is not anticipated the Village would issue any further debt—meaning the utility rate is likely to stay the same until additional improvements are approved.

Stormwater Utility Feasibility Study

Questions about the stormwater utility fee and current rate can be directed to the Village’s Stormwater Utility Customer Support at 847-716-3549 or

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