Des Plaines, IL Environmental Rules: Stormwater Management (2026)

Des Plaines is located within Cook County and subject to the MWRD Watershed Management Ordinance, the controlling stormwater regulation for the metropolitan Chicago region. The WMO requires stormwater detention, water quality controls, erosion and sediment control, and floodplain protection for development projects exceeding regulatory thresholds (typically 1/2 acre of disturbance for water quality and 1 acre or 25,000 square feet of new impervious area for detention). Detention facilities must be sized to limit post-development discharge to specified release rates, and water quality volume must be treated through best management practices such as bioretention, vegetated swales, or proprietary filters. Des Plaines's Department of Public Works/Engineering reviews development plans for compliance. The City is highly flood-prone due to its position along the Des Plaines River and Higgins Creek and participates in the National Flood Insurance Program with active floodplain regulations and ongoing flood mitigation projects. Residential lot grading must drain away from the foundation and not discharge concentrated flows onto neighboring properties.