Water Quality in San Tan Valley, AZ: 62 Violations — Grade C
Grade C · Score 69/100 · 4 water systems · Updated 2026-05-03
San Tan Valley's water has moderate compliance issues. Residents in affected areas should consider filtration.
Data: EPA Safe Drinking Water Information System (SDWIS) Last verified: 2026-05-03
The compliance record maintained by the EPA for San Tan Valley, AZ documents 62 water violations — each tied to a specific public water system and assigned a violation category in the federal Safe Drinking Water dataset.
Water Quality by ZIP Code in San Tan Valley
Water quality varies across San Tan Valley's 2 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 85140 | C | 69 | 31 | 0 | View report → |
| 85143 | C | 69 | 31 | 0 | View report → |
Water Quality Overview
San Tan Valley, Arizona receives a water quality grade of C with an overall score of 69 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 4 water systems serving San Tan Valley have accumulated 62 EPA violations (all monitoring/reporting type). These violations are tracked across 2 ZIP codes serving approximately 98,772 people.
What Grade C Means
A grade of C indicates moderate compliance issues. San Tan Valley's water systems have some violations that warrant attention. While the water may still be safe for most people, residents in affected ZIP codes should consider additional testing or filtration.
Lead Levels
The average 90th percentile lead level across San Tan Valley water systems is 0.0018 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
San Tan Valley is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving San Tan Valley
San Tan Valley is served by 4 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 98,772 people across 2 ZIP codes.
Each water system is identified by a Public Water System ID (PWSID) and is required to:
- Test for over 90 regulated contaminants on a regular schedule
- Report results to the EPA and state regulators
- Issue an annual Consumer Confidence Report (CCR) to all customers
- Take corrective action when violations occur
The EPA has taken 20 enforcement actions against water systems serving San Tan Valley. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in San Tan Valley
Enter your ZIP code on ZipCheckup to see your specific water system data, including contaminant levels, violation history, and safety scores
Request your CCR — your water utility must provide an annual Consumer Confidence Report with detailed test results for all monitored contaminants
Get a home test — certified kits cost $20–$50 and test for lead, bacteria, and common contaminants. Professional lab tests ($150–$400) cover a broader panel
Consider filtration — NSF-certified filters can remove specific contaminants. Reverse osmosis removes the broadest range; activated carbon is effective for chlorine and many organics
Check for advisories — monitor your local utility website and local news for boil water advisories or system alerts
Contaminants Detected in San Tan Valley Water Systems
The following contaminants have been detected or caused violations across San Tan Valley's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | N/A | 22 | 2 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 10 | 2 | No |
| Lead | Inorganic | 0.015 mg/L | 8 | 2 | No |
| Lead and Copper Rule | Treatment Technique | N/A | 6 | 2 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 4 | 2 | No |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 2 | 2 | No |
MCL = Maximum Contaminant Level (EPA enforceable standard). Health-based violations indicate levels that may pose direct health risks.
EPA Enforcement History
The EPA and state regulators have taken 9 enforcement actions against water systems serving San Tan Valley. Recent actions:
| Date | Action Type |
|---|---|
| 2025-06-17 | State Informal Action |
| 2025-06-17 | State Informal Enforcement |
| 2025-02-07 | State Order Extension |
| 2025-02-06 | State Order Extension |
| 2025-02-05 | State Order Extension |
| 2025-01-30 | State Informal Action |
| 2025-01-30 | State Informal Enforcement |
| 2025-01-29 | State Informal Action |
| 2025-01-29 | State Order Extension |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-06-17.
San Tan Valley vs. Nearby Arizona Cities
How San Tan Valley's water quality compares to similar cities in Arizona:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| San Tan Valley | C | 62 | 4 | 98,772 |
| Queen Creek | B | 105 | 3 | 97,812 |
| Maricopa | C | 288 | 5 | 101,115 |
| Flagstaff | C | 120 | 5 | 92,709 |
Common Questions About San Tan Valley Water
These are the most common questions residents search for about water quality in San Tan Valley, Arizona:
Is San Tan Valley water hard or soft? Water hardness varies by source. San Tan Valley's 4 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink San Tan Valley tap water? San Tan Valley's water receives a grade of C (69/100). No health-based violations have been recorded, but home testing is always recommended.
What is the best water filter for San Tan Valley? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
San Tan Valley vs. Arizona Average
Understanding how San Tan Valley compares to the broader Arizona average helps contextualize your local water quality. Factors like water source, treatment methods, and infrastructure age all contribute to differences between cities in the same state.
To see how individual neighborhoods compare, check the ZIP code reports below — water quality can vary significantly even within San Tan Valley.
ZIP Codes in San Tan Valley
San Tan Valley spans 2 ZIP codes. The ZIP with the lowest water quality score is 85140. Each ZIP code has its own water quality profile based on the specific water system serving that area. Check each ZIP code for detailed contaminant data, violation history, and system information.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
- Enforcement: EPA ECHO database
- Filter recommendations: NSF/ANSI certified products
Updated daily.