What matters for project planning
Honestly, very little of the city's stormwater and floodplain framework reaches an interior bathroom. Land-disturbing permits, on-site stormwater control facilities and the countywide ordinance enforced by DuPage County Stormwater Management all concern what happens outside the building envelope. The one exception is scale: where a parcel sits inside the mapped floodplain that Naperville has adopted DuPage County's regulations for, work extensive enough relative to the structure's value can engage additional requirements. Otherwise the permits that matter to you are the plumbing and electrical ones, and those are about the fixtures rather than the site.
Official sources
Verify the property, not just the city
Citywide context cannot establish a parcel’s flood zone, historic designation, stream buffer, 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.