Arizona Water Quality Rankings 2026: Best & Worst Cities

This page ranks the 37 Arizona cities whose water systems we have matched to EPA records. Every city starts at 100 points and loses points for health-based EPA violations in the last five years (SDWIS 2026Q2), its most recent Lead and Copper Rule 90th-percentile result, PFAS detected in EPA's 2023–2026 UCMR5 monitoring, and 2012–2019 compliance samples that averaged near or above a limit. Letters follow fixed bands (A ≥90, B ≥80, C ≥70, D ≥60, F below 60). Cities run from the highest score (Apache Junction) down to the lowest (Bullhead City); ties are ordered by population served. See the full scoring methodology for every deduction and the data vintages. 3 further Arizona cities are listed at the bottom without a grade because we have not yet matched them to an EPA water system.

What your city's grade means

An A or B grade points to water that consistently tests within federal safety limits, while a C suggests moderate issues worth watching and a D or F flags contaminants or compliance problems serious enough to act on. These grades describe system-level water leaving the treatment plant — they can't account for your home's own plumbing, so older houses with lead service lines or fixtures can add contaminants after the water arrives. For a contaminant-by-contaminant view, see the Arizona contaminant breakdown or drill into the county-level rankings.

What Arizona residents should do

• Find your city in the ranking below and open its full report for its violation history, lead results and PFAS table.
• See how Arizona compares against the best-rated and worst-rated cities nationwide.
• Test your home's water if you have concerns — the most common issues involve lead, PFAS, and arsenic.
• Check whether your utility still has lead service lines in Arizona — EPA's inventory counts lead pipes by water system, a risk that plant-level grades cannot capture. Read the lead guide for testing and filter options.
• If treatment makes sense for your situation, compare certified water filters matched to the contaminants found in your area.

This ranking covers 40 Arizona cities. 37 of them are matched to an active EPA-registered community water system (PWSID). Those 37 systems report serving 5,364,504 people in EPA's Safe Drinking Water Information System (SDWIS).

Of 37 cities of the 40 Arizona cities we can grade from EPA records, 22 cities (60%) grade B or better, 7 sit in the C range and 8 grade D or F. The average score is 81/100. 3 cities are not graded because they have not been matched to an EPA system yet.

EPA records 17 health-based violations in the last five years across 8 cities, and 1 city still has a health-based violation listed as unresolved. Monitoring and reporting violations (575 in the same window) are paperwork lapses and cost far fewer points.

37 cities have a Lead and Copper Rule 90th-percentile result from 2020 or later: 1 city at 5 ppb or more.

EPA's UCMR5 PFAS monitoring (2023–2026) covers 37 cities: PFAS were detected in 21 cities, and PFOA or PFOS reached EPA's 4 ppt limit in 10 cities.

Apache Junction scores highest (100) and Bullhead City lowest (44), a 56-point spread.

The clearest hard data for Arizona is EPA's service line inventory, updated 2026-08-18 (Q2 2026). 944 Arizona systems inventoried 2,586,547 service lines: 6 confirmed lead plus 2,825 galvanized lines requiring replacement, spread across 2 systems. The bigger number is 714,350 lines (28%) whose material is still unknown — more than one line in four — and EPA treats unknown lines as possible lead until a utility verifies them.

Of the 37 city-linked Arizona utilities with an inventory on file, 7 report at least one lead or galvanized-requiring-replacement line, 9 report none but still have a quarter or more of their lines unverified, and 21 report no lead with most lines verified. The largest, PHOENIX CITY OF (Phoenix, 1,695,000 served), reports 0 lead lines and 506 galvanized requiring replacement.

Our Arizona water guide flags arsenic, fluoride, chromium-6, and nitrates as the contaminants of regional concern. Arsenic (EPA MCL 0.010 mg/L (10 ppb)) is linked to skin damage, circulatory problems and increased cancer risk; Fluoride (EPA MCL 4.0 mg/L (secondary standard 2.0 mg/L)) above the limit can cause bone pain and tenderness and mottled teeth in children; Chromium (EPA MCL 0.1 mg/L for total chromium; no separate federal limit for chromium-6) can cause allergic dermatitis; the hexavalent form is a suspected carcinogen when ingested; Nitrate (EPA MCL 10 mg/L (as nitrogen)) can cause methemoglobinemia ("blue baby syndrome") in infants under six months.

Source water explains a lot of the pattern in Arizona. Arsenic, fluoride, and uranium are naturally occurring and tend to show up in groundwater, leaching from bedrock into aquifers rather than arriving from pollution. Nitrate follows fertilizer, manure and septic loading, so it is most often a concern for systems drawing shallow groundwater in farm regions. Chromium is tied to specific sites — industrial discharges, firefighting-foam use at airports and bases — rather than to geology, so contamination is local and can affect either source type. Lead is different again: it enters after treatment from service lines and household plumbing, which is why the inventory figures above matter more than plant-level results. The Consumer Confidence Report your Arizona utility mails each year states whether your system draws surface water or groundwater.

The best water quality in Arizona is found in Apache Junction with a score of 100/100 and a grade of A. This puts Apache Junction among the top-performing cities in the country for drinking water safety.

The most concerning water quality is in Bullhead City scoring 44/100 with a grade of F. Residents may want to consider home water testing and filtration options.

The statewide average score is 81/100, which is 7 points below the national average of 88/100. Only 41% of Arizona cities score above the national average, suggesting statewide water quality improvement is needed.