Tap Water Quality Report
Tap water quality in MARICOPA, Arizona
Tap water in MARICOPA, Arizona receives a grade of F (52/100) from TapWaterSafety.org. It's served by GW SANTA CRUZ WATER CO. The most significant water quality concerns are: Arsenic significantly above health guideline; Chromium (hexavalent) significantly above health guideline; Total trihalomethanes (TTHMs) significantly above health guideline. Data sources: EPA SDWIS, EPA ECHO, EWG Tap Water Database.
What's in MARICOPA's tap water
Top water quality concerns identified by the EPA and Environmental Working Group across the utility serving MARICOPA.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 7.11 ppb, 1777x above the EWG health guideline of 0.004 ppb.
Chromium (hexavalent) significantly above health guideline
Moderate concernChromium (hexavalent) detected at 6.3 ppb, 315x above the EWG health guideline of 0.02 ppb.
Total trihalomethanes (TTHMs) significantly above health guideline
Moderate concernTotal trihalomethanes (TTHMs) detected at 14.0 ppb, 93x above the EWG health guideline of 0.15 ppb.
EPA compliance record
Official U.S. EPA records for GW SANTA CRUZ WATER CO (system ID AZ0411131) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Stage 1 Disinfectants and Disinfection Byproducts Rule | Missed testing or reporting | 11/01/2025 | Open |
| Public Notice Rule and Revised PN Rule | Other (e.g. public notice) | 07/19/2025 | Open |
| Stage 2 Disinfectants and Disinfection Byproducts Rule | Missed testing or reporting | 04/01/2024 | Open |
| Arsenic Rule | Missed testing or reporting | 01/01/2021 | Open |
| Inorganic Chemicals | Missed testing or reporting | 01/01/2021 | Open |
| Synthetic Organic Chemicals | Missed testing or reporting | 01/01/2021 | Open |
| Radionuclides and Revised Rad Rule | Missed testing or reporting | 07/01/2023 | Open |
| Revised Total Coliform Rule | Contaminant above the legal limit | 08/01/2025 | Open |
| Revised Total Coliform Rule | Missed testing | 09/01/2023 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Recommended filters for MARICOPA
Filters matched to the specific contaminants in MARICOPA's water supply.
Reverse osmosis certified for arsenic (NSF/ANSI 58)
$429-$599Reverse osmosis certified under NSF/ANSI 58 for arsenic is the most reliable home option.
Carbon filter certified for VOCs (NSF/ANSI 53)
$180-$599Activated carbon is effective for disinfection byproducts like TTHM. Look for NSF/ANSI 53 VOC or chloroform reduction.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
All contaminants detected in MARICOPA's tap water
Every contaminant identified, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal. Why we show multiple standards →
| Contaminant | Detected | EWG US health-based |
EPA US legal |
EU DWD Europe |
WHO global |
CA PHG strictest US |
Tested sample year |
Status |
|---|---|---|---|---|---|---|---|---|
| Arsenic Heavy metal |
7.11 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 1777× over |
| Chromium (hexavalent) Heavy metal |
6.3 ppb | 0.02 | — | — | — | — | — | 315× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
14.0 ppb | 0.15 | 80.0 | 100 | — | — | — | 93× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
4.4 ppb | 0.06 | — | — | — | — | — | 73× over |
| Nitrate and nitrite Inorganic |
6.7 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 48× over |
| Nitrate Inorganic |
6.03 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 43× over |
| Haloacetic acids (HAA5) Disinfection byproduct |
1.84 ppb | 0.1 | 60.0 | 60 | — | — | — | 18× over |
| Uranium Radiological |
7.07 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 16× over |
| Radium, combined (-226 and -228) Radiological |
0.09 pCi/L | 0.05 | 5.0 | — | — | — | — | 1.8× over |
| Chlorate Disinfection byproduct |
148.0 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Vanadium Other |
7.18 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Molybdenum Other |
3.6 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
2.13 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Manganese Heavy metal |
0.0388 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Fluoride Inorganic |
1.25 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.78 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
179.0 ppb | — | — | — | — | — | — | Below guideline |
All values in the unit of the detected level. Red cells indicate the detected level exceeds that standard. Some contaminants have limits in some jurisdictions but not others (shown as —). The "Tested" column shows the year each contaminant sample was collected.
Sources: US EPA, EU Drinking Water Directive 2020/2184, WHO Guidelines, California OEHHA PHGs, EWG Tap Water Database.
Treatment plant contact info
For service issues, water quality concerns, or to request a Consumer Confidence Report from GW SANTA CRUZ WATER CO.