What matters for project planning
The City of Naperville is the local permitting authority for land-disturbing activity and requires property owners to maintain on-site stormwater control facilities; Naperville has adopted DuPage County's floodplain regulations for the portions of the city within DuPage County, and Naperville's own stormwater plan relies on storm sewers, detention basins, and overflow routes. DuPage County Stormwater Management enforces the countywide Stormwater & Floodplain Ordinance across five program areas -- Watershed Management, Floodplain Mapping, Water Quality, Regulatory Services, and Flood Operations -- and the county's building code requires soil testing in areas likely to have expansive clay soils.
Official sources
Verify the property, not just the city
Citywide context cannot establish a parcel’s flood zone, historic designation, permit requirements, soil conditions, or concealed construction. Confirm those items with the appropriate authority and selected provider before work begins.
Sources reviewed 2026-07-26. External requirements and maps can change.