What was found in Tucson's water
The level at the city's main supplier, the highest level anywhere in the city, the EPA limit for each, and where every figure comes from.
| Contaminant | Level vs EPA limit | Suppliers | Source |
|---|---|---|---|
| Nitrate | 4741.5 µg/L 47% of the EPA limit 10000 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 12050 µg/L — LAKEWOOD ESTATES WATER COMPANY · 722 people · 2019 | 73/82 | SYR4 |
| Nitrate-Nitrite | 4160 µg/L 42% of the EPA limit 10000 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 11695 µg/L — LAKEWOOD ESTATES WATER COMPANY · 722 people · 2019 | 62/82 | SYR4 |
| Fluoride | 626.15 µg/L 16% of the EPA limit 4000 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 3400 µg/L — METROPOLITAN DWID - DIABLO VILLAGE · 5,542 people · 2019 | 60/82 | SYR4 |
| Copper | 197.5 µg/L 15% of the EPA limit 1300 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2017
Highest in the city: 666 µg/L — SPANISH TRAIL WATER COMPANY · 3,822 people · 2018 | 77/82 | SYR4 |
| Nitrite | 400 µg/L 40% of the EPA limit 1000 µg/L Highest in the city: RIVERSIDE APARTMENTS · 75 people · 2013 | 2/82 | SYR4 |
| Barium | 110.25 µg/L 5.5% of the EPA limit 2000 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 245 µg/L — METROPOLITAN DWID - DIABLO VILLAGE · 5,542 people · 2019 | 63/82 | SYR4 |
| Lithium | 63.7 µg/L No EPA limit set Main supplier: TUCSON CITY OF · 732,906 people · 2025
Highest in the city: 228 µg/L — FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 13/82 | UCMR-5 |
| Total Haloacetic Acids (HAA5) | 2.57 µg/L 4.3% of the EPA limit 60 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 54.25 µg/L — SANDARIO WATER COMPANY · 870 people · 2019 | 21/82 | SYR4 |
| Xylenes, Total | 7.025 µg/L 0.1% of the EPA limit 10000 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 49.06 µg/L — METROPOLITAN DWID - LAZY B · 77 people · 2019 | 9/82 | SYR4 |
| Lead | 1.4925 µg/L 10% of the EPA limit 15 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2017
Highest in the city: 44.15 µg/L — THIM WATER COMPANY 2 · 247 people · 2017 | 72/82 | SYR4 |
| TTHM | 22.05 µg/L 28% of the EPA limit 80 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 38.6 µg/L — TRAILS WEST MHP · 500 people · 2019 | 43/82 | SYR4 |
| Bromoform | 24.845 µg/L No EPA limit set Highest in the city: SANDARIO WATER COMPANY · 870 people · 2019 | 16/82 | SYR4 |
| Di(2-ethylhexyl) Phthalate | 3.72 µg/L 62% of the EPA limit 6 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 18.91 µg/L — HALCYON ACRES WATER USERS ASSOCIATION · 215 people · 2019 | 9/82 | SYR4 |
| Combined Uranium | 12.92 µg/L 43% of the EPA limit 30 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 18 µg/L — LAKEWOOD ESTATES WATER COMPANY · 722 people · 2019 | 8/82 | SYR4 |
| Di(2-ethylhexyl) Adipate | 15.75 µg/L 3.9% of the EPA limit 400 µg/L Highest in the city: HALCYON ACRES WATER USERS ASSOCIATION · 215 people · 2019 | 1/82 | SYR4 |
| Arsenic | 6.7335 µg/L 67% of the EPA limit 10 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 10.3 µg/L — TIERRA LINDA HOA WATER COMPANY · 266 people · 2019 | 54/82 | SYR4 |
| Gross Alpha, Excl. Radon And U | 2.69 pCi/L 18% of the EPA limit 15 pCi/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 9.62 pCi/L — SIETE CASAS JOINT VENTURE · 25 people · 2017 | 8/82 | SYR4 |
| Cyanide | 9.09 µg/L 4.5% of the EPA limit 200 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019 | 1/82 | SYR4 |
| Selenium | 2.961 µg/L 5.9% of the EPA limit 50 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 8.75 µg/L — FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2019 | 5/82 | SYR4 |
| Dibromochloromethane | 8.425 µg/L No EPA limit set Highest in the city: VAIL WATER COMPANY · 17,500 people · 2019 | 13/82 | SYR4 |
| Chromium | 7.98 µg/L 8% of the EPA limit 100 µg/L Highest in the city: THIM UTILITY COMPANY - RANCHO VISTA · 105 people · 2019 | 33/82 | SYR4 |
| Trichloroethylene | 2.05 µg/L 41% of the EPA limit 5 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 6.4 µg/L — SILVER CHOLLA LLC · 168 people · 2019 | 4/82 | SYR4 |
| Ethylbenzene | 1.1 µg/L 0.2% of the EPA limit 700 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 5.6315 µg/L — METROPOLITAN DWID - LAZY B · 77 people · 2019 | 4/82 | SYR4 |
| Bromodichloromethane | 4.65 µg/L No EPA limit set Highest in the city: VAIL WATER COMPANY · 17,500 people · 2019 | 5/82 | SYR4 |
| cis-1,2-Dichloroethylene | 2.72 µg/L 3.9% of the EPA limit 70 µg/L Highest in the city: METROPOLITAN DWID · 45,570 people · 2019 | 1/82 | SYR4 |
| Tetrachloroethylene | 2.7 µg/L 54% of the EPA limit 5 µg/L Highest in the city: VOYAGER WATER COMPANY · 3,209 people · 2019 | 1/82 | SYR4 |
| Combined Radium (-226 And -228) | 1.06 pCi/L 21% of the EPA limit 5 pCi/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 2.5 pCi/L — MISSION PALMS APARTMENTS · 720 people · 2014 | 24/82 | SYR4 |
| Dibromoacetic Acid | 2.37 µg/L No EPA limit set Highest in the city: LAKEWOOD ESTATES WATER COMPANY · 722 people · 2019 | 6/82 | SYR4 |
| 1,1-Dichloroethylene | 1.8 µg/L 26% of the EPA limit 7 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019 | 3/82 | SYR4 |
| Antimony, Total | 1.8 µg/L 30% of the EPA limit 6 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019 | 2/82 | SYR4 |
| Chloroform | 1.725 µg/L No EPA limit set Highest in the city: VAIL WATER COMPANY · 17,500 people · 2019 | 3/82 | SYR4 |
| Dichloroacetic Acid | 1.1 µg/L No EPA limit set Highest in the city: VAIL WATER COMPANY · 17,500 people · 2019 | 2/82 | SYR4 |
| P-Dichlorobenzene | 0.7900 µg/L 1.1% of the EPA limit 75 µg/L Highest in the city: CATALINA VILLAGE · 107 people · 2019 | 1/82 | SYR4 |
| Styrene | 0.6200 µg/L 0.6% of the EPA limit 100 µg/L Highest in the city: CATALINA VILLAGE · 107 people · 2019 | 1/82 | SYR4 |
| Mercury | 0.6100 µg/L 31% of the EPA limit 2 µg/L Highest in the city: CACTUS COUNTRY RV RESORT · 420 people · 2015 | 1/82 | SYR4 |
| Toluene | 0.5000 µg/L 0.1% of the EPA limit 1000 µg/L Highest in the city: METROPOLITAN DWID - LAZY B · 77 people · 2019 | 1/82 | SYR4 |
| Simazine | 0.1100 µg/L 2.8% of the EPA limit 4 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019
Highest in the city: 0.1440 µg/L — CAMMIES FOOTHILLS VISTA MHC · 62 people · 2019 | 6/82 | SYR4 |
| Pentachlorophenol | 0.1200 µg/L 12% of the EPA limit 1 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019 | 1/82 | SYR4 |
| Atrazine | 0.1058 µg/L 3.5% of the EPA limit 3 µg/L Main supplier: TUCSON CITY OF · 732,906 people · 2019 | 1/82 | SYR4 |
| Lead | 0.00065 mg/L 4.3% of the EPA limit 0.0150 mg/L Main supplier: TUCSON CITY OF · 732,906 people · 2023
Highest in the city: 0.0270 mg/L — RINCON COUNTRY EAST RV PARK · 912 people · 2025 | 82/82 | LCR |
| PFHXS | 0.0090 µg/L No EPA limit set Highest in the city: FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 2/82 | UCMR-5 |
| Pfba | 0.0081 µg/L No EPA limit set Main supplier: TUCSON CITY OF · 732,906 people · 2025 | 1/82 | UCMR-5 |
| PFOS | 0.0060 µg/L No EPA limit set Highest in the city: FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 1/82 | UCMR-5 |
| PFOA | 0.0050 µg/L No EPA limit set Highest in the city: FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 1/82 | UCMR-5 |
| PFBS | 0.0048 µg/L No EPA limit set Highest in the city: METROPOLITAN DWID · 45,570 people · 2025 | 2/82 | UCMR-5 |
| Pfpea | 0.0040 µg/L No EPA limit set Highest in the city: FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 1/82 | UCMR-5 |
| Pfhxa | 0.0030 µg/L No EPA limit set Highest in the city: FLOWING WELLS IRRIGATION DISTRICT · 16,000 people · 2023 | 1/82 | UCMR-5 |
Each bar shows the measured level as a share of the EPA limit: green is
well under, amber is close to it, red is over. For lead and copper the
limit applies to exactly the 90th-percentile figure shown, so red there
means a real exceedance. For everything else the limit applies to a
running annual average while the figure is the 95th percentile of the
system's samples — over 100% is worth reading, but is not by itself a
violation.
Formal violations are listed separately.
These are the utilities' own EPA-reported results, not a city-wide
average. A detection means the lab measured the
substance — it isn't the same as exceeding a legal limit. Hover a source
tag to see the EPA program and years behind each figure.
Water suppliers serving Tucson
The 50 largest of 82 suppliers serving Tucson, by population served.
Frequently asked questions about Tucson tap water
Is Tucson tap water safe to drink?
EPA testing detected 47 contaminants in the water serving Tucson. A detection isn't the same as a violation — most detected levels are within federal limits. Check the level and source for each contaminant above, and your utility's annual Consumer Confidence Report for the official compliance status.
How many water suppliers serve Tucson?
82 public water suppliers report drinking-water monitoring for Tucson, Arizona to the EPA. Each is listed above with its population served.
What contaminants are in Tucson's water?
The contaminants EPA monitoring detected in Tucson include Nitrate, Nitrate-Nitrite, Fluoride, Copper, Nitrite. The full list, with the level at the main supplier and the data source, is in the table above.
Where does this data come from?
Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.