Maricopa Water Quality

116 EPA violations on record (most recent 2025). Nitrate enters water mainly from fertilizer runoff, septic systems, and animal waste. High levels can interfere with the blood's ability to carry oxygen, a special danger for infants. Long-term low-level exposure has also been linked to elevated cancer risk in some studies.

48 EPA violations on record (most recent 2024). Arsenic is a naturally occurring element that dissolves into groundwater from rock and is also released by mining and industry. Long-term exposure is associated with several cancers and with skin, cardiovascular, and developmental harm. It is common in parts of the Southwest.

5 EPA violations on record (most recent 2021). Fluoride occurs naturally in groundwater and is also added by many utilities to reduce tooth decay. At high natural levels it can damage developing teeth and, over long exposure, weaken bones. The federal limit targets these high-level health effects rather than the low levels used for dental benefit.

7 EPA violations on record (most recent 2024). HAA5 are a second group of chlorine disinfection byproducts formed when chlorine reacts with organic matter in water. Long-term exposure is associated with increased cancer risk and possible developmental effects. They commonly occur together with trihalomethanes.

7 EPA violations on record (most recent 2024). TTHM form when chlorine used to disinfect water reacts with natural organic matter. Long-term exposure has been linked to increased cancer risk and to harm in pregnancy. Levels often rise in warmer months and in systems with more organic material.

3 EPA violations on record (most recent 2023). Radium is a naturally radioactive element that leaches from rock into groundwater. Long-term exposure increases the risk of bone cancer and other cancers because it concentrates in bone. The federal limit covers the combined activity of radium-226 and radium-228.

2 EPA violations on record (most recent 2023). Beta and photon emitters are radioactive contaminants that can come from natural deposits or from nuclear activity. Long-term exposure increases cancer risk. The federal limit is expressed as an annual dose rather than a simple concentration.

2 EPA violations on record (most recent 2021). Cadmium enters water from corroded galvanized pipes and from industrial and mining discharges. Long-term exposure mainly damages the kidneys and can weaken bones. It is toxic even at low levels over time.

2 EPA violations on record (most recent 2023). Radium-226 is a naturally radioactive isotope that seeps from rock into groundwater. Over years of exposure it concentrates in bone and raises the risk of bone and other cancers. It is regulated together with radium-228 under the combined radium standard.

2 EPA violations on record (most recent 2021). Barium dissolves into water naturally from rock and can also come from drilling and industrial discharges. Drinking elevated levels over time can raise blood pressure and stress the cardiovascular system. It is fairly common in some groundwater sources.

2 EPA violations on record (most recent 2021). Mercury reaches water from natural deposits, industrial runoff, and discarded products. Long-term exposure harms the kidneys and nervous system. It is tightly regulated because of its toxicity at low concentrations.

2 EPA violations on record (most recent 2021). Selenium is a naturally occurring element that is a necessary nutrient at trace levels but toxic in excess. Long-term high exposure can damage the nervous system, hair, and nails. It enters water from natural deposits and from irrigation drainage.

1 EPA violation on record (most recent 2023). Uranium occurs naturally in rock and dissolves into groundwater, with extra contributions from mining in some regions. It is both a radioactive and a toxic metal; long-term exposure mainly damages the kidneys and increases cancer risk. It is widespread in Western groundwater.

1 EPA violation on record (most recent 2021). Atrazine is one of the most widely used weed killers and reaches water through agricultural runoff. It is an endocrine disruptor associated with reproductive and developmental effects, and concentrations tend to spike seasonally after application. It is most common in farming regions.

1 EPA violation on record (most recent 2021). PFOA is a long-lived "forever chemical" once used to make nonstick and stain-resistant products. It builds up in the body over time and is associated with certain cancers, immune effects, and developmental harm. EPA finalized a strict drinking-water limit for it in 2024.

1 EPA violation on record (most recent 2021). PFOS is another "forever chemical" from older firefighting foams and consumer coatings. Like PFOA it accumulates in the body and is linked to immune, thyroid, liver, and developmental effects. EPA set an enforceable limit for it in 2024.

Maricopa's water is very hard. Hardness isn't a health risk, but it drives scale on fixtures and water heaters, shortens appliance life, and leaves skin and hair dry.