Tour the Westside Storm Sewer

Westside Storm Sewer

Location: West of Ridge Road.
History: Started at Kenilworth Gardens in 1920s, expanded in 1930s and ’50s.

System For:

Weather-Rain-icon from iconarchive dot comStorm runoff

Storm Sewer Specs:

  • 49.79 miles of sewer lines.
  • A network of sewer lines flow into a single Lake Ave trunk.
  • The Lake Ave pump station lifts the stormwater, so it can drain (by gravity) into the North Branch of the Chicago River, via a culvert and smaller pipe.
  • The two outflows discharge directly into the river–no water treatment.

Storm Sewer Issues:

  • Low-lying, flat landscape has very little natural drainage (such as streams).
  • Old and new properties have inadequate stormwater management.
  • Renovations, new construction, and commercial and public projects are producing more impermeable and paved surfaces, which creates more runoff.
  • Climate change brings higher annual rainfalls, with more intense storms.
  • Old connections from sump pumps and downspouts add excess stormwater to the system. (Direct connections are no longer allowed for new construction.)
  • When leaky storm sewers get overloaded, pressure builds, stormwater is forced out, then it infiltrates nearby sanitary sewers, causing sewage backups.
  • There are too few storm sewer lines, with too little capacity for 2-year rainstorms.
  • Widespread flooding and property damage occur every couple of years.

Recent Storm Sewer Projects:

  • Wilmette cleans 20 percent of drains and inspects 10 percent of the pipes annually, as part of annual maintenance required by the Illinois EPA for a Municipal Separate Storm Sewer System (MS4) permit.
  • Repair crews have used Closed Circuit Televising (CCTV) to inspect pipes for structural damage.
  • Crews have repaired severe damage and relined pipes to seal up cracks.


Storm Sewer Map
Source: Village of Wilmette, Separate Storm Sewer System Stormwater Management Report, by Christopher B. Burke Engineering (January 2015), Exhibit 5.


Current Storm Sewer Drainage
Source: The Village of Wilmette Engineering Dept., Separate Storm Sewer Study Final Presentation, by Brigitte Berger (January 2015), p 7.


Wilmette’s storm sewer is regulated under the EPA’s Municipal Separate Storm Sewer Systems (MS4) program. (The acronym stands for “Municipal” and four “s” words–get it?)

To find out more, see the MS4 Main Page, which explains that “to prevent harmful pollutants from being washed or dumped into an MS4, operators must obtain a NPDES permit and develop a stormwater management program.”

Here’s Wilmette’s most recent MS4 Report, submitted to the Illinois Environmental Protection Agency in March 2015. The report describes how Wilmette is meeting operation and maintenance requirements, as specified by the Illinois Environmental Protection Act (415 ILCS 5/).

Fact check:

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