Maricopa County Tap Water Quality: What Phoenix Homeowners Are Actually Drinking in 2025

Phoenix tap water in 2025 comes from two main sources: the Colorado River delivered through the Central Arizona Project canal, and Salt River Project reservoirs fed by snowmelt from the White Mountains. Both surface water supplies are treated with chloramine, a blend of chlorine and ammonia that utilities use because it produces fewer trihalomethanes than free chlorine over long distribution systems. The result is water that meets all federal Maximum Contaminant Levels but carries measurable levels of hardness, disinfection chemicals, and trace contaminants that vary by neighborhood and season. The U.S. Geological Survey documents Phoenix metro water hardness in the range of 150 to 250 milligrams per liter (about 8.8 to 14.6 grains per gallon), placing virtually every Phoenix household in the very hard water classification. The City of Phoenix publishes an annual Water Quality Report at phoenix.gov/waterservices that covers every regulated contaminant measured in the distribution system.

Where does Phoenix tap water come from?

The City of Phoenix draws surface water from two primary systems. The Central Arizona Project delivers Colorado River water via a 336-mile canal from Lake Havasu to the Phoenix metro area. The Salt River Project operates a chain of reservoirs on the Salt and Verde Rivers northeast of Phoenix. Both systems are surface water sources, meaning the water carries organic matter that reacts with disinfectants to form byproducts during treatment. Phoenix also maintains a groundwater banking program, using treated reclaimed water and stored groundwater to supplement supply during peak demand. The treatment process for surface water includes coagulation, sedimentation, filtration, and disinfection with chloramine as the final step. The EPA's Overview of Drinking Water Treatment Technologies at epa.gov documents the standard surface water treatment train and why each step is required. Understanding the source matters because surface water from desert river systems carries a mineral and organic load that determines what treatment produces and what arrives at your tap.

What contaminants are in Phoenix tap water?

The City of Phoenix 2023 Consumer Confidence Report, available at phoenix.gov/waterservices, documents all regulated contaminants detected in the distribution system during the reporting year. The key parameters Phoenix homeowners ask about most often are listed below with their reported ranges and regulatory context. All values are from publicly available Phoenix Water quality data or federal sources. Verify the most current figures by downloading the latest Consumer Confidence Report directly from phoenix.gov/waterservices, as the city updates it each year.

• Hardness: Phoenix surface water typically ranges from 150 to 250 mg/L (approximately 8.8 to 14.6 grains per gallon). The USGS Water Science School (usgs.gov) classifies water above 180 mg/L as very hard. There is no federal MCL for hardness because it is not a health hazard, but it accelerates scale in pipes and appliances.
• Total Trihalomethanes (TTHMs): The City of Phoenix 2023 CCR reports approximately 18 ppb. Federal MCL is 80 ppb. Phoenix uses chloramine specifically to keep TTHMs well below the limit.
• Haloacetic Acids (HAA5s): Reported at approximately 12 ppb in the 2023 CCR. Federal MCL is 60 ppb.
• PFAS (PFOA and PFOS): The EPA finalized new Maximum Contaminant Levels in April 2024 at 4 parts per trillion each (epa.gov/pfas-drinking-water-regulation). Several Maricopa County systems detected PFAS during EPA UCMR 5 monitoring from 2023 to 2025. Compliance deadline for water systems is 2029.
• Nitrate: The Phoenix 2023 CCR reports nitrate levels well below the MCL of 10 mg/L as nitrogen. Nitrate in Phoenix surface water is low but can be elevated in groundwater zones near agricultural areas.
• Arsenic: Arizona groundwater in some areas carries naturally elevated arsenic. Phoenix surface water arsenic levels are typically below 5 ppb. The federal MCL for arsenic is 10 ppb.
• Total Dissolved Solids (TDS): Phoenix tap water typically measures 500 to 700 ppm TDS. There is no federal MCL for TDS, but the EPA secondary standard (non-enforceable) is 500 ppm. High TDS affects taste and is relevant if you use reverse osmosis for drinking water.

How hard is Phoenix water compared to the rest of the United States?

The U.S. Geological Survey has mapped groundwater and surface water hardness across the country, and the Phoenix metro area consistently ranks among the hardest in the nation. USGS circular data on water quality in the western United States (pubs.usgs.gov) shows that the Colorado River watershed naturally carries high mineral loads from the sedimentary rock formations it crosses before reaching Arizona. Salt River Project water adds calcium and magnesium from volcanic and limestone geology in the White Mountains and Mazatzal ranges. The result is tap water that is two to three times harder than the national median. Most Phoenix metro homes fall in the 12 to 22 grains per gallon range when measured at the tap, because individual service zones that draw more groundwater, particularly in Mesa, Gilbert, and Peoria, can significantly exceed the surface water hardness baseline. Scale from this hardness level reduces water heater efficiency, spots glassware, and shortens the life of dishwashers, washing machines, and ice makers. Schedule a free water test at the link below to get the measured hardness at your specific tap rather than relying on a zone average.

What are PFAS and do they appear in Phoenix area water?

Per- and polyfluoroalkyl substances are a family of thousands of synthetic chemicals that persist in the environment because the carbon-fluorine bond does not break down naturally. The EPA finalized enforceable Maximum Contaminant Levels for PFOA and PFOS at 4 parts per trillion in April 2024, with a compliance deadline of 2029 for water systems (epa.gov/pfas-drinking-water-regulation). Under the EPA's fifth Unregulated Contaminant Monitoring Rule, which ran from 2023 through 2025, public water systems across Arizona were required to test for 29 PFAS compounds. Several Maricopa County utilities detected PFAS at or above the EPA minimum reporting level during the monitoring period, according to EPA UCMR 5 data. Phoenix homeowners who want to reduce PFAS at the kitchen tap while water systems work toward compliance can use a reverse osmosis system certified to NSF/ANSI Standard 58, which is documented by the EPA as an effective point-of-use reduction method. Standard pitcher filters and most refrigerator filters are not certified for PFAS reduction. Verify NSF 58 certification before purchasing. See what a reverse osmosis system looks like installed in a Phoenix home at the link below.

Why does Phoenix water smell like chlorine or chemicals?

Phoenix uses chloramine as its residual disinfectant. Chloramine is formed by combining chlorine and ammonia at a controlled ratio. It is added after filtration and travels with the water through the distribution system to suppress bacterial growth from the treatment plant to your tap. The smell some residents notice is chloramine and its reaction products, not free chlorine. Chloramine is less volatile than free chlorine, which is why it persists longer in the distribution system. For households sensitive to the taste and smell, a whole-home carbon filtration system installed on the main water line removes chloramine before water reaches any fixture, including showers, kitchen taps, and appliances. Catalytic carbon specifically is more effective than standard granular activated carbon at reducing chloramine because chloramine does not break down by adsorption alone but requires a catalytic reaction. The EPA chloramines fact sheet at epa.gov documents the chemistry and why utilities choose this approach. Call us or book your free water test online and we will measure your actual chloramine levels and review your options without any obligation.

How to read the Phoenix Consumer Confidence Report

The City of Phoenix publishes its annual Water Quality Report each July at phoenix.gov/waterservices, covering the prior calendar year. The report lists every regulated contaminant detected in the distribution system, the measured range or average, the federal Maximum Contaminant Level or Maximum Contaminant Level Goal, and the likely source. To use it effectively: find the parameter you want to understand, look at the measured value column against the MCL column, and note the unit of measurement (ppb, ppt, mg/L, or NTU). Secondary standards, which cover parameters like TDS, hardness, and taste, are listed separately and are not enforceable. The EPA also maintains a searchable Consumer Confidence Report database at epa.gov/ccr where you can look up any public water system by name or zip code. If your Phoenix address is served by a supplemental groundwater zone rather than a pure surface water zone, your CCR locational data may show higher hardness and different contaminant profiles than the system-wide averages. A water treatment professional who measures your tap directly can tell you which service zone you are actually in and what is currently coming out of your tap. We provide that measurement at no charge to Phoenix metro homeowners.

• Phoenix Water Quality Report: phoenix.gov/waterservices (updated annually each July)
• EPA CCR Database: epa.gov/ccr (searchable by utility name or zip code)
• EPA PFAS MCL Rule: epa.gov/pfas-drinking-water-regulation (April 2024 final rule)
• USGS Water Quality Data: waterdata.usgs.gov (real-time and historical Arizona water quality measurements)
• Arizona Department of Environmental Quality drinking water: azdeq.gov/drinking-water (utility compliance records)

What water treatment makes sense for a Phoenix home?

Most Phoenix households benefit from addressing two separate problems with two complementary systems. Hardness in the 12 to 22 GPG range damages appliances and requires a whole-home water softener sized to your measured grains per gallon and household flow. Chloramine, disinfection byproducts, and dissolved solids including any detected PFAS are best addressed at the kitchen drinking tap with a reverse osmosis system certified to NSF/ANSI Standard 58. A whole-home carbon pre-filter upstream of the softener also reduces chloramine throughout the home, protecting the softener resin and addressing shower and bath exposure to volatile compounds. The right combination depends on your measured tap water results, not a zone average. Aqua Wellness serves Phoenix, Scottsdale, Tempe, Mesa, Chandler, and Ahwatukee. We carry the WQA Certified credential, hold a BBB A+ rating, and have installed treatment systems in more than 200 Phoenix area homes. Every install includes a 25-year warranty on tank and valve components and is completed in approximately four hours.