Yes, rainwater collection is legal in Illinois, but compliance hinges on adherence to state and local water rights laws, structural safety codes, and health regulations. The Illinois State Water Survey confirms no statewide ban, yet municipal ordinances and permit requirements may apply, particularly for larger systems.
Key Regulations for Rainwater Collection in Illinois
- Water Rights Compliance: Illinois follows the reasonable use doctrine, meaning collected rainwater must not interfere with downstream water rights under the Illinois Water Use Act. Systems exceeding 1,000 gallons require permits from the Illinois Department of Natural Resources (IDNR).
- Structural and Plumbing Codes: Systems must comply with the Illinois Plumbing Code (2019 edition) and local building codes. Cross-connection with potable water systems is prohibited without backflow prevention devices certified by the Illinois Environmental Protection Agency (IEPA).
- Health and Safety Standards: The Illinois Department of Public Health mandates that rainwater used for potable purposes undergo filtration and disinfection meeting NSF/ANSI Standard 61. Non-potable uses (e.g., irrigation) must avoid contamination of groundwater per IEPA guidelines.
Local jurisdictions, such as the Chicago Department of Water Management, impose additional restrictions. For example, Chicago requires permits for systems over 200 gallons and prohibits roof runoff from mixing with municipal water supplies. Recent 2026 IEPA draft rules may tighten monitoring for large-scale agricultural systems, emphasizing sediment control and storage tank integrity. Always consult municipal authorities and IDNR before installation to ensure alignment with evolving compliance frameworks.