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Stormwater Sewers

The June 2018 flash floods will not soon be forgotten. Both as a City, and as residents, we all have the responsibility to ensure we are better prepared for the next historical storm.

While the City is responsible for upgrading storm sewer infrastructure, residents can help as well. Learn more about how the City reimburses residents for investing in their property by exploring our Stormwater Best Management Practices Program.

What is a Storm Sewer?
A storm drain, stormwater drain, or storm sewer system is designed to drain excess rain and groundwater from paved streets, parking lots, sidewalks, and roofs. They are fed by street gutters on most motorways, freeways and other busy roads, as well surface runoff from other areas during rain events. Most storm sewer systems are designed to handle smaller more frequent storms. During heavier, infrequent storms some street ponding is expected, and sometimes water may run to a natural drainageway.

How Do Storm Sewers Function?
Inlet: There are two main types of stormwater drain (sewer) inlets; side and grated. Side (or curb inlets) are located adjacent to the curb and rely on the ability of the opening to capture water flow. Grated inlets have gratings or grids to prevent large objects and debris from falling into the sewer system. However, the bars are fairly widely spaced so that the flow of water is not impeded. 

Piping: Pipes can come in many different shapes (rectangular, square, oval and more commonly, circular) and have many different features. Several different materials can also be used such as brick, concrete or less frequently, metal.

Outlet: Most drains have a single large exit at their point of discharge (often covered by grating) into a canal, river, lake or reservoir. In Des Moines, all stormwater eventually drains into the Des Moines or Raccoon Rivers, either through a direct discharge from the storm sewer system or after making its way to larger creek, such as Walnut or Fourmile Creek.  Typically there are no treatment facilities in the piping system other than catch-basins. In some cases, storm drains may discharge into manmade excavations known as detention or retention ponds before being discharged to water body.

Report a Problem

To report any stormwater pollution concerns like:

  • Drainage concerns
  • Unauthorized storm sewer or waterway connections
  • Polluted runoff

Contact the City's 24-Hour Hotline at (515) 283-4950 or submit a concern online


Rules, Regulations and Rates

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