Pima County · Arizona · EPA SDWIS 2026Q2
Tucson Water Quality
What's in Tucson's water
PFAS (forever chemicals)
1.5×above guideline
Detected above the EPA's 4 ppt limit for PFOA/PFOS — the "forever chemicals" linked to cancer and immune effects. Compounds found: PFBA, PFBS, PFHxA, PFHxS, PFOA, PFOS, PFPeA.
Nitrate
Violation on record
23 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.
Fluoride
Violation on record
19 EPA violations on record (most recent 2025). 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.
Arsenic
Violation on record
12 EPA violations on record (most recent 2025). 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.
Total Trihalomethanes (TTHM)
Violation on record
21 EPA violations on record (most recent 2025). 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.
Haloacetic Acids (HAA5)
Violation on record
21 EPA violations on record (most recent 2025). 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.
Water hardness
very hard
Tucson'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.
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- 732,906
- PWSID
- AZ0410112
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