Arizona Cities With the Most Contaminants on Record
Arizona public water systems with the most distinct contaminants on the EPA record, ranked.
172 cities on this list · updated 2026
| # | City | Contaminants on record |
|---|---|---|
| 1 | Bullhead Citytop: Nitrate | 17 |
| 2 | Florencetop: Arsenic | 17 |
| 3 | Maricopatop: Nitrate | 16 |
| 4 | Phoenixtop: Arsenic | 14 |
| 5 | Gilberttop: Total Trihalomethanes (TTHM) | 13 |
| 6 | Apache Junctiontop: Nitrate | 12 |
| 7 | Buckeyetop: Haloacetic Acids (HAA5) | 12 |
| 8 | Flagstafftop: Arsenic | 11 |
| 9 | Bonitatop: Haloacetic Acids (HAA5) | 11 |
| 10 | El Miragetop: Arsenic | 10 |
| 11 | Casa Grandetop: Arsenic | 9 |
| 12 | Chandlertop: Arsenic | 8 |
| 13 | Prescotttop: Uranium | 8 |
| 14 | Peoriatop: Nitrate | 7 |
| 15 | Catalinatop: Haloacetic Acids (HAA5) | 7 |
| 16 | Pinetoptop: Total Trihalomethanes (TTHM) | 7 |
| 17 | Tucsontop: Nitrate | 6 |
| 18 | Mesatop: Nitrate | 6 |
| 19 | Yumatop: Arsenic | 6 |
| 20 | Kingmantop: Arsenic | 6 |
| 21 | Goodyeartop: Haloacetic Acids (HAA5) | 6 |
| 22 | Surprisetop: Arsenic | 5 |
| 23 | Sierra Vistatop: Atrazine | 5 |
| 24 | Show Lowtop: Selenium | 5 |
| 25 | Saffordtop: Fluoride | 5 |
| 26 | Cottonwoodtop: Arsenic | 5 |
| 27 | Globetop: Haloacetic Acids (HAA5) | 5 |
| 28 | Stanfieldtop: Nitrate | 5 |
| 29 | New Rivertop: Arsenic | 5 |
| 30 | Litchfield Parktop: Total Trihalomethanes (TTHM) | 4 |
Methodology. Ranked by the number of distinct contaminants with an EPA record for each city's primary water system. Built from public U.S. EPA drinking-water records (SDWIS violations + UCMR5 PFAS monitoring) for community water systems. A higher count or a lower Water Score reflects what's on the federal record — not a judgment of any utility. Meeting legal limits is not the same as zero risk.
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