Will County, IL Environmental Rules: Stormwater Management (2026)
Key Facts
- Governing law
- Will County Code § 55.021
- Permit required
- Stormwater management permit before development
- Detention trigger
- 5+ acre subdivision or 1+ acre nonresidential
- Max civil fine
- $750 per day of violation
- Scope
- Unincorporated county and non-certified municipalities
Summary
Will County requires a stormwater management permit before any development that could raise flood elevations or shift drainage costs onto neighbors, with detention required for most subdivisions and multi-family or nonresidential sites.
(A) Requirements applicable to all developments. No development shall: (1) Result in any new or additional expense to any person other than the developer for flood protection; or (2) Increase flood elevations or decrease flood conveyance capacity upstream or downstream of the area under the ownership or control of the developer.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2025 S-25: Supplement contains: Local legislation current through Ordinance No. 24-100, passed 4-18-2024 and Res. 23-387, passed 11-16-2023; and State legislation approved through 2024 Pamphlet #2).
Full Breakdown
The Will County Stormwater Management Ordinance (WCSMO), Chapter 55, bars any development from raising flood elevations, reducing flood conveyance, or pushing flood-protection costs onto someone other than the developer, and requires a stormwater management permit before construction begins. Detention (site runoff storage) is mandatory for subdivisions of more than two single-family homes on five-plus acres, multi-family or nonresidential projects over one acre, and roadway work over two acres. The County Administrator and Director enforce the WCSMO directly in unincorporated Will County and in municipalities that have not been certified to run their own program; certified cities such as Joliet administer their own equivalent stormwater regulations.
Violations & Fines
Violating the WCSMO is a civil offense: fines run $25 to $750 per day of violation, and the Administrator or Director may revoke a stormwater permit or issue a stop-work order.
Frequently Asked Questions
Does Will County's stormwater ordinance apply inside Joliet or Bolingbrook?
When does a project need on-site detention in Will County?
What happens if I develop without a stormwater permit?
Sources & Official References
Other rules in Will County
Compare Will County to another location·View the Illinois environmental rules overview
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