The safety of municipal drinking water is a common concern, as it is a foundational public health service. In Tucson, the water utility consistently meets or surpasses all federal regulatory health standards. While the water is safe when it leaves the treatment facilities, understanding the source, testing process, and potential household-level variables provides a complete picture of tap water quality.
Tucson’s Water Sources and Infrastructure
Tucson’s municipal water supply relies on a blend of sources, primarily the Colorado River and local groundwater reserves. The Central Arizona Project (CAP) delivers Colorado River water through a 336-mile canal system. CAP water has become the primary renewable source since the 1990s, reducing historic reliance on groundwater pumping and addressing aquifer overdraft.
The CAP water is often used to recharge the local aquifer by pumping it into settling basins where it percolates back into the ground. This process allows the river water to mix with native groundwater, which is then pumped out and delivered to customers. This strategy helps manage resources sustainably and addressed initial public concerns about the taste and odor of unblended CAP water. Local groundwater remains a significant component, ensuring a resilient supply strategy.
Regulatory Compliance and Current Water Quality Status
Tucson Water operates under the guidelines of the U.S. Environmental Protection Agency (EPA) Safe Drinking Water Act and is overseen by the Arizona Department of Environmental Quality (ADEQ). The utility conducts extensive monitoring, collecting samples from over 170 wells, 60 reservoirs, and 271 sampling stations to ensure compliance with all federal and state health standards.
One common local issue is water hardness, caused by high concentrations of dissolved minerals like calcium and magnesium. Tucson’s water is moderately hard, which can lead to scale buildup on appliances and a distinct taste. However, this mineral content does not pose a health risk.
Tucson Water has also taken proactive measures regarding emerging contaminants, notably per- and polyfluoroalkyl substances (PFAS). The utility has been voluntarily testing since 2018 and maintains operational standards that are often more stringent than the federal requirements, even before the EPA established new Maximum Contaminant Levels (MCLs).
The utility has removed multiple production wells from service that had detectable levels of PFAS and invested in treatment facilities, such as the Advanced Oxidation Process Water Treatment Facility. For instance, the operational standard for PFOA and PFOS is less than 2 parts per trillion (ppt), exceeding the EPA’s enforceable MCLs. This proactive approach ensures the finished water product delivered to the community remains safe, despite localized groundwater contamination issues.
Factors Affecting Water Safety at the Tap
While the water is safe when it leaves the municipal distribution system, quality can change after it enters private property plumbing. The primary household concern is the potential for metal leaching, specifically lead and copper, from older plumbing materials. Homes built before 1986 may have internal plumbing or fixtures containing lead solder or components that can corrode and release metal into the water.
Tucson Water actively manages corrosion control within the distribution system to minimize the risk of metal leaching. However, the service line from the meter to the home and the internal fixtures are the responsibility of the property owner. The utility is currently working to inventory all water service line materials as part of the revised federal Lead and Copper Rule.
The safe and reliable water supplied by the utility is lead-free, but as it travels through older pipes, the potential for exposure exists. A simple and effective solution to minimize this risk is to flush the water line before consuming the water. Running the cold water tap for 30 seconds to two minutes, especially after the water has been sitting unused for several hours, helps clear any water that may have absorbed metals.
It is also recommended to use only cold water for drinking, cooking, and making baby formula, as hot water can dissolve metals more quickly. Boiling water will not remove lead and may concentrate the contaminant.
How to Verify Water Quality Information
Residents can easily access detailed, site-specific information about their tap water quality directly from the utility. Every year, Tucson Water publishes its Annual Water Quality Report, also known as the Consumer Confidence Report (CCR), which is required by the EPA. This report provides comprehensive data on the water source, detected contaminants, and the utility’s compliance status.
The CCR is typically published in June and is available on the Tucson Water website, often alongside an interactive water quality map. By entering a street address or intersection, a customer can view specific water quality parameters from a nearby sampling point. This transparency allows customers to review the exact testing results for their service area.