Yes, rainwater collection is legal in Arizona, but compliance hinges on adherence to state and local water rights frameworks. The Arizona Department of Water Resources (ADWR) permits residential rainwater harvesting under specific conditions, prioritizing non-impairment of existing water rights. Municipalities like Tucson and Phoenix impose additional restrictions, particularly for potable systems.
Key Regulations for Rainwater Collection in Arizona
- ADWR Permitting Thresholds: Systems exceeding 100 gallons of storage require ADWR approval under A.R.S. § 45-172, ensuring compliance with groundwater protection statutes. Smaller systems (≤100 gallons) are exempt but must avoid interference with prior appropriation rights.
- Local Municipal Ordinances: Cities like Phoenix mandate permits for systems connected to potable water supplies, while Tucson enforces Ordinance 11620 requiring backflow prevention devices for non-potable uses.
- Water Rights Priority: Harvesting must not diminish flows in regulated rivers (e.g., Colorado, Gila) under A.R.S. § 45-141, aligning with the 2026 ADWR groundwater management plan updates emphasizing sustainable extraction limits.
Rainwater collection is permissible for non-potable uses (e.g., irrigation, toilet flushing) without impairing senior water rights. Potable systems face stricter scrutiny, including health department approvals and filtration standards. Violations may trigger ADWR enforcement actions, including fines or system shutdowns. Consult county-specific guidelines, as rural areas often lack formal restrictions but may require well-drilling permits for storage tanks.