What was found in Maricopa'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 | 6600 µg/L 66% of the EPA limit 10000 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 31300 µg/L — PAPAGO BUTTE DWID · 530 people · 2019 | 6/10 | SYR4 |
| Nitrate-Nitrite | 5506 µg/L 55% of the EPA limit 10000 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 19000 µg/L — PAPAGO BUTTE DWID · 530 people · 2012 | 6/10 | SYR4 |
| Fluoride | 2100 µg/L 53% of the EPA limit 4000 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 3074 µg/L — COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 6/10 | SYR4 |
| Lithium | 263 µg/L No EPA limit set Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2024 | 2/10 | UCMR-5 |
| Copper | 142 µg/L 11% of the EPA limit 1300 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 218 µg/L — COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 7/10 | SYR4 |
| Barium | 68.2 µg/L 3.4% of the EPA limit 2000 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 90.8 µg/L — MARICOPA CONSOLIDATED DWID · 928 people · 2018 | 6/10 | SYR4 |
| TTHM | 37 µg/L 46% of the EPA limit 80 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 60.8 µg/L — MARICOPA CONSOLIDATED DWID · 928 people · 2019 | 7/10 | SYR4 |
| Combined Uranium | 21 µg/L 70% of the EPA limit 30 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019 | 2/10 | SYR4 |
| Chromium | 6.97 µg/L 7% of the EPA limit 100 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 18.75 µg/L — PAPAGO BUTTE DWID · 530 people · 2018 | 6/10 | SYR4 |
| Lead | 2.395 µg/L 16% of the EPA limit 15 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 16.48 µg/L — COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 7/10 | SYR4 |
| Selenium | 3.82 µg/L 7.6% of the EPA limit 50 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018
Highest in the city: 14.25 µg/L — MARICOPA CONSOLIDATED DWID · 928 people · 2018 | 2/10 | SYR4 |
| Arsenic | 8.36 µg/L 84% of the EPA limit 10 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 11.7 µg/L — THUNDERBIRD FARMS DWID · 2,231 people · 2019 | 6/10 | SYR4 |
| Total Haloacetic Acids (HAA5) | 9.105 µg/L 15% of the EPA limit 60 µg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 10.8 µg/L — COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 7/10 | SYR4 |
| Gross Alpha, Excl. Radon And U | 3.32 pCi/L 22% of the EPA limit 15 pCi/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2018 | 1/10 | SYR4 |
| Bromoform | 2.39 µg/L No EPA limit set Highest in the city: COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 1/10 | SYR4 |
| Combined Radium (-226 And -228) | 0.8700 pCi/L 17% of the EPA limit 5 pCi/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2019
Highest in the city: 2 pCi/L — COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 3/10 | SYR4 |
| Dibromoacetic Acid | 1.095 µg/L No EPA limit set Highest in the city: COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 1/10 | SYR4 |
| Dibromochloromethane | 1.095 µg/L No EPA limit set Highest in the city: COPPER MOUNTAIN RANCH CFD · 1,071 people · 2019 | 1/10 | SYR4 |
| Xylenes, Total | 0.7140 µg/L 0% of the EPA limit 10000 µg/L Highest in the city: VALLE ESCONDIDO · 405 people · 2019 | 1/10 | SYR4 |
| Lead | 0.0 mg/L 0% of the EPA limit 0.0150 mg/L Main supplier: GW SANTA CRUZ WATER CO · 84,000 people · 2024
Highest in the city: 0.0035 mg/L — GW SANTA CRUZ WATER -TWIN HAWKS WATER · 57 people · 2024 | 10/10 | LCR |
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 Maricopa
| Supplier | Population served |
|---|---|
| GW SANTA CRUZ WATER CO | 84,000 |
| THUNDERBIRD FARMS DWID | 2,231 |
| GW SANTA CRUZ WATER - MARICOPA SW | 1,170 |
| COPPER MOUNTAIN RANCH CFD | 1,071 |
| MARICOPA CONSOLIDATED DWID | 928 |
| PAPAGO BUTTE DWID | 530 |
| VALLE ESCONDIDO | 405 |
| NEW SADDLEBACK VISTA | 100 |
| AMERICAN REALTY MORTGAGE COMPANY | 60 |
| GW SANTA CRUZ WATER -TWIN HAWKS WATER | 57 |
Frequently asked questions about Maricopa tap water
Is Maricopa tap water safe to drink?
EPA testing detected 20 contaminants in the water serving Maricopa. 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 Maricopa?
10 public water suppliers report drinking-water monitoring for Maricopa, Arizona to the EPA. Each is listed above with its population served.
What contaminants are in Maricopa's water?
The contaminants EPA monitoring detected in Maricopa include Nitrate, Nitrate-Nitrite, Fluoride, Lithium, Copper. 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.