Pima County, AZ Landscaping Rules: Rainwater Harvesting (2026)

Arizona HB 2675 (codified in ARS 33-1816 for HOAs) prohibits homeowner associations from banning rainwater harvesting systems, reflecting strong state policy favoring water conservation in the arid Southwest. Pima County encourages both active (cistern/tank) and passive (earthworks/berms) rainwater harvesting. No county permit is required for residential cisterns under 2,500 gallons. Larger systems may need a building permit depending on structural connections. Gray water systems are also encouraged under Arizona Department of Environmental Quality (ADEQ) General Permit 4.02, which allows residential gray water use (from laundry, bathroom sinks, showers) for landscape irrigation without a site-specific permit if the system produces fewer than 400 gallons per day. Pima County Cooperative Extension and the Watershed Management Group (a Tucson-based nonprofit) provide technical assistance. The Tucson region receives approximately 11-12 inches of annual rainfall, primarily during summer monsoon season (July-September), making storage during monsoon critical for year-round landscape irrigation.