Latest Testing Results

• Lead Levels: The most recent testing period shows 90th percentile lead levels below EPA action levels. Phoenix is actively completing its lead service line inventory under the revised Lead and Copper Rule Improvements (LCRI), notifying residents with galvanized or unknown service line materials as part of federally required assessments. Visit pipes.phoenix.gov to check your service line status.
• Testing Scope: Phoenix conducts rigorous testing for nearly 200 substances to meet and exceed government safety standards, including proactive monitoring for PFAS, 1,4-dioxane, perchlorate, and emerging pharmaceuticals. The city operates its own certified laboratory in partnership with research institutions.
• Compliance Status: Phoenix water met all federal and state drinking water standards through the most recently assessed quarter (April–June 2024 per EPA ECHO). However, EWG analysis of 2013–2023 utility data identifies 23 total contaminants, with 8 exceeding health guidelines — including arsenic at 1,026 times the EWG health guideline. Check our national water quality checker to compare Phoenix against other cities.
• PFAS Monitoring: Under UCMR 5 (2023–2025), Phoenix participated in nationwide monitoring for 29 PFAS and lithium. The Arizona Department of Environmental Quality (ADEQ) also operates a statewide PFAS programme backed by $5 million in state funding and approximately $63.5 million in federal Bipartisan Infrastructure Law support, ensuring comprehensive testing across Arizona public water systems. PFOA and PFOS MCLs of 4 ppt remain in effect following EPA’s May 2025 announcement; PFOS compliance deadlines have been extended with a federal exemption framework under consideration. For the latest developments, see our water quality news feed.

Water Sources and Treatment

• Multiple Water Sources: Phoenix’s water portfolio draws on Salt and Verde River water (approximately 25% of the Greater Phoenix supply), Colorado River water via the Central Arizona Project (approximately 29%), and groundwater (approximately 34% across the broader region). Surface water treated at Phoenix’s treatment plants accounts for 97% of the city’s direct supply. The Colorado River Basin was upgraded from a Tier 2 shortage to a Tier 1 shortage in 2024, easing some supply pressure but long-term drought management remains critical.
• Advanced Water Treatment: Phoenix operates eight water treatment facilities processing surface water and groundwater using advanced technologies including membrane filtration, ozonation, and biological activated carbon. The oldest plant dates from the early 1950s; all have been modernised over the years, with the most recent facility completed in 2007.
• Groundwater Management: Phoenix has historically discontinued use of contaminated groundwater wells with naturally occurring arsenic and fluoride, blending high-quality aquifer water with treated surface water. The 1980 Arizona Groundwater Management Act provides legal infrastructure for 100-year water supply planning across Active Management Areas including Greater Phoenix.

Sustainability Initiatives

• Artificial Groundwater Recharge: Phoenix operates extensive underground storage facilities, banking surplus Colorado River and treated surface water in Sonoran Desert aquifers during wet years for use during droughts — a cornerstone of its 100-year assured water supply strategy.
• Water Recycling Leadership: The city’s reclaimed water system delivers treated wastewater for irrigation, industrial uses, and groundwater recharge. The Tres Rios Environmental Restoration Project restores nearly 700 acres along the Salt River, creating a natural ecosystem that treats water and supports wildlife while providing recreational space.
• Conservation Success: Despite significant population growth since the 1950s, Phoenix consumes approximately the same total water volume today as it did then, demonstrating the effectiveness of its long-running conservation programmes. Phoenix was a founding member of the regional Water Use It Wisely campaign, one of the longest-running conservation initiatives in the country.
• Colorado Resiliency Fund: Established in 2014, this fund allocates an average of $5.5 million annually to strengthen water security — including strategic well-sharing with local utility partners, underground water banking, and shortage-year lease options with higher-priority water rights holders.

Infrastructure Improvements

• Capital Improvement Programme: Phoenix maintains a rolling five-year Capital Improvement Programme (CIP) reviewed annually by the Phoenix City Council. Projects cover water treatment plant upgrades, reservoir rehabilitation, water main and sewer replacement, regulatory compliance modifications, and automation improvements.
• Pipe Network Scale: The city’s distribution network spans 7,000 miles of water lines and 5,000 miles of sewer lines, with the largest transmission main measuring 108 inches in diameter. Ongoing assessments prioritise end-of-life replacements to minimise lifecycle costs and maintain reliable delivery.
• Engineering Apprenticeship: In 2025, Phoenix Water Services launched its first-ever engineering apprenticeship programme to attract the next generation of water industry professionals — recognising that long-term infrastructure quality depends as much on workforce development as on capital investment.

Nearby city water quality comparisons: Scottsdale | Mesa | Chandler | Tempe | Tucson. For a broader picture see our Arizona water quality overview. If your area has issued a boil water advisory, check our live US boil water notices tracker.