Water Quality Report · Updated October 07, 2026
EPCOR - SAN TAN
EPCOR - SAN TAN delivers tap water graded C (65/100) by TapWaterSafety.org. The utility serves approximately 87,435 residents in JOHNSON RANCH, Arizona using groundwater. The most significant water quality concerns are: Arsenic significantly above health guideline; Chromium (hexavalent) significantly above health guideline; Nitrate and nitrite significantly above health guideline. For questions, the utility can be reached at 602-722-4100.
Is JOHNSON RANCH tap water safe to drink?
EPCOR - SAN TAN delivers tap water that earns a grade of C (65/100) from TapWaterSafety.org — an average rating, with several contaminants above health guidelines but generally compliant with US legal limits.
The utility serves 87,435 residents in JOHNSON RANCH, drawing from groundwater.
Public testing data identifies 10 contaminants in this water above EWG's health-based guidelines, including: Arsenic, Chromium (hexavalent), Nitrate and nitrite, Nitrate, Haloacetic acids (HAA9), Uranium, Total trihalomethanes (TTHMs), Radium, combined (-226 and -228), Dibromochloromethane, Bromoform. For most residents, a properly certified home filter at the kitchen tap is the most cost-effective way to reduce exposure to whatever's in your water. See our filter recommendations below, matched specifically to this utility's contaminant profile.
EPA compliance record
Official U.S. EPA records for EPCOR - SAN TAN (system ID AZ0411128) for the last 3 years. Checked 2026-10-07.
| Rule | Type | Since | Status |
|---|---|---|---|
| Stage 1 Disinfectants and Disinfection Byproducts Rule | Missed testing or reporting | 04/01/2024 | Open |
| Volatile Organic Chemicals | Missed testing or reporting | 01/01/2024 | Open |
| Nitrate Rule | Missed testing or reporting | 01/01/2024 | Open |
Source: U.S. EPA Enforcement and Compliance History Online (ECHO), from the Safe Drinking Water Information System. See EPA's full report.
Quick actions for JOHNSON RANCH residents
Top concerns in this water
Based on the most recent EPA and EWG data, these are the most significant water quality issues for EPCOR - SAN TAN.
Arsenic significantly above health guideline
Moderate concernArsenic detected at 3.78 ppb, 946x above the EWG health guideline of 0.004 ppb.
Chromium (hexavalent) significantly above health guideline
Moderate concernChromium (hexavalent) detected at 3.47 ppb, 173x above the EWG health guideline of 0.02 ppb.
Nitrate and nitrite significantly above health guideline
Moderate concernNitrate and nitrite detected at 6.21 ppm, 44x above the EWG health guideline of 0.14 ppm.
Contact EPCOR - SAN TAN
Reach the utility directly for service issues, water quality concerns, or to request your Consumer Confidence Report.
General Contact
Treatment Plant
Recommended water filters for JOHNSON RANCH
Filters matched to the specific contaminants in this 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.
Disclosure: TapWaterSafety earns a commission from purchases made through these links. This does not influence our scoring methodology or filter selection.
Score breakdown
This utility's overall score of 65/100 breaks down across five weighted components. Read the full methodology →
Contaminants detected — international standards comparison
Every contaminant detected, compared side-by-side against US EPA legal limits, the EU Drinking Water Directive (2020/2184), WHO Guidelines, and California's Public Health Goal (the strictest US benchmark). 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 |
3.78 ppb | 0.004 | 10.0 | 10 | 10 | 0.004 | — | 946× over |
| Chromium (hexavalent) Heavy metal |
3.47 ppb | 0.02 | — | — | — | — | — | 173× over |
| Nitrate and nitrite Inorganic |
6.21 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 44× over |
| Nitrate Inorganic |
5.81 ppm | 0.14 | 10.0 | 11.3 | 11.3 | 10 | — | 41× over |
| Haloacetic acids (HAA9) Disinfection byproduct |
1.02 ppb | 0.06 | — | — | — | — | — | 17× over |
| Uranium Radiological |
4.89 pCi/L | 0.43 | 20.0 | 30 | 30 | 0.43 | — | 11× over |
| Total trihalomethanes (TTHMs) Disinfection byproduct |
1.29 ppb | 0.15 | 80.0 | 100 | — | — | — | 8.6× over |
| Radium, combined (-226 and -228) Radiological |
0.31 pCi/L | 0.05 | 5.0 | — | — | — | — | 6.1× over |
| Dibromochloromethane Disinfection byproduct |
0.375 ppb | 0.1 | — | — | — | — | — | 3.8× over |
| Bromoform Disinfection byproduct |
1.15 ppb | 0.5 | — | — | — | — | — | 2.3× over |
| Vanadium Other |
13.6 ppb | 21.0 | — | — | — | — | — | Below guideline |
| Barium Heavy metal |
40.5 ppb | 700.0 | 2000.0 | — | 1300 | 2000 | — | Below guideline |
| Molybdenum Other |
1.5 ppb | 40.0 | — | — | — | — | — | Below guideline |
| Selenium Heavy metal |
1.07 ppb | 30.0 | 50.0 | 20 | 40 | 30 | — | Below guideline |
| Manganese Heavy metal |
1.04 ppb | 100.0 | — | 50 | 80 | — | — | Below guideline |
| Chlorate Disinfection byproduct |
2.0 ppb | 210.0 | — | — | — | — | — | Below guideline |
| Strontium Radiological |
0.83 ppb | 1500.0 | — | — | — | — | — | Below guideline |
| Chromium (total) Heavy metal |
3.37 ppb | — | 100.0 | — | — | — | — | Below guideline |
| Fluoride Inorganic |
0.453 ppm | — | 4.0 | 1.5 | 1.5 | — | — | Below guideline |
| Germanium Other |
0.385 ppb | — | — | — | — | — | — | Below guideline |
| Lithium Other |
112.7 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 (4th ed.), California OEHHA PHGs, EWG Tap Water Database.
EPCOR - SAN TAN service area
This water system serves 1 community in Pinal County, Arizona. Click any city for its dedicated tap water quality page.
Find the right filter for JOHNSON RANCH water
Browse filter categories by water-quality concern. Each option below is NSF-certified for the matched contaminant type.