What matters for project planning
Will County lies within the Des Plaines River watershed, where urban flooding is typically basement flooding and sewer backup -- a documented, ongoing concern in regional stormwater planning. The City of Joliet enacted its own Stormwater Management Ordinance and serves as the permitting authority for land-disturbing activity, requiring on-site stormwater control facilities from developers and property owners alike. Parts of Joliet sit within a mapped 100-year flood zone near the Des Plaines River, so parcel-specific flood status should be checked before exterior, foundation, or grading work begins.
Official sources
Verify the property, not just the city
None of the citywide context above substitutes for a parcel-level check -- it can't tell you one specific lot's flood zone, historic status, permit needs, soil type, or what's actually built into the walls. Homeowners should confirm the Joliet parcel's flood zone, historic-district status, and permit requirements with the relevant authority first.
Sources reviewed 2026-07-26. Both the city ordinance and the county code can be amended after this page was written -- treat everything above as a starting point, not the final word.