Storm drain inlet protection measures are devices designed to prevent sediment from entering the storm drain system. They do this by surrounding or covering the inlet with a filtering material. They are one of what the Environmental Protection Agency (EPA) calls “Best Management Practices” (BMPs), measures homebuilders are required to implement onsite to manage stormwater. Uncontrolled stormwater from construction sites can potentially carry sediment, debris, pesticides, and other substances into U.S. waters.
According to the EPA, the primary stormwater pollutant at a construction site is sediment. Sediment includes any small particulate, such as soil, sand, and minerals, that’s eroded by water, wind, or other natural force. Stormwater runoff from an unstabilized site can result in the loss of approximately 35 to 45 tons of sediment per acre each year.
Storm drain inlet protection measures focus on preventing sediment from entering the storm drain system. The EPA refers to this type of BMP as a sediment control. Sediment controls treat sediment as a pollutant, working to keep it out of U.S. waters.
Storm drain inlet protection measures are implemented before a site is disturbed and are removed upon the completion of the project. There are numerous types of storm drain inlet protection measures. The type that’s selected depends on the type of inlet, the slope, and the volume of flow.
In general, these measures are practical for areas receiving relatively clean runoff that’s not heavily laden with sediment. They can handle a drainage area no greater than one acre per inlet. To increase their effectiveness, they should be combined with other BMPs, such as a sediment basin. 
Storm drain inlet protection measures are one way to control sediment onsite. They should be used in conjunction with other sediment controls, as well as erosion controls, which are the primary means of preventing stormwater pollution. Sediment controls provide a necessary second line of defense.
For more information about managing stormwater, visit the EPA, or check out BuildIQ University’s online training courses: SWPPP Compliance; SWPPP Runoff, Erosion, and Sediment Controls; and SWPPP Good Housekeeping Measures.
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