Cook County, IL Landscaping Rules: Rainwater Harvesting (2026)
Key Facts
- Governs
- Unincorporated Cook County only
- Small-barrel exception
- No treatment under 360 gallons, subsurface/drip
- Permit trigger
- Plumbed catchment systems need Commissioner approval
- Marking required
- CAUTION: NONPOTABLE RAINWATER, DO NOT DRINK
- Collection standard
- Rooftop systems must meet ARCSA/ASPE/ANSI 63
Summary
In unincorporated Cook County, any rainwater catchment system that feeds irrigation lines, toilets, or other plumbing must be approved by the Building Commissioner and follow ARCSA/ASPE/ANSI 63 collection standards.
The installation, construction, alteration, and repair of rainwater catchments systems intended to supply uses such as water closets, urinals, trap primers for floor drains and floor sinks, irrigation, industrial processes, water features, cooling tower makeup and other uses shall be approved by the Building Commissioner. Rainwater catchment systems for collecting precipitation from rooftops shall comply with ARCSA/ASPE/ANSI 63.
Full Breakdown
The County's Plumbing Code (Chapter 118, Article V) treats a rooftop rainwater catchment system like any other plumbing installation: no permit is issued until plumbing plans are submitted and approved by the Building Commissioner, and rooftop collection piping must meet the ARCSA/ASPE/ANSI 63 standard. Systems feeding irrigation, toilets, urinals, or cooling towers need water treatment matched to the use, but treatment is waived for subsurface or drip irrigation, or nonsprinkled aboveground irrigation, storing 360 gallons or less. Nonpotable lines and hose bibbs must carry a "CAUTION: NONPOTABLE RAINWATER, DO NOT DRINK" marking, and an abandoned tank must be drained and capped or removed.
Violations & Fines
Installing a plumbed catchment system without Building Commissioner approval, skipping the required water treatment for larger or sprinkled systems, cross-connecting to the potable water supply, or leaving an abandoned tank unplugged can draw a stop-work order or code citation.
Frequently Asked Questions
Do I need a permit for a simple rain barrel in unincorporated Cook County?
Does this rule apply in Chicago or other Cook County suburbs?
Sources & Official References
Other rules in Cook County
Compare Cook County to another location·View the Illinois landscaping rules overview
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