Water Quality in Maricopa, AZ: 288 Violations — Grade C
Grade C · Score 56/100 · 5 water systems · Updated 2026-05-03
Maricopa'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
SDWIS records for Maricopa, AZ show 288 EPA violations documented for the local water supply — these span the full range of reportable events from health-based exceedances to monitoring and reporting lapses registered with the federal program.
Water Quality by ZIP Code in Maricopa
Water quality varies across Maricopa's 4 ZIP codes. Check your specific ZIP for detailed contaminant data.
| ZIP Code | Grade | Score | Violations | Health | |
|---|---|---|---|---|---|
| 85238 | D | 50 | 72 | 27 | View report → |
| 85138 | C | 58 | 72 | 27 | View report → |
| 85139 | C | 58 | 72 | 27 | View report → |
| 85239 | C | 58 | 72 | 27 | View report → |
Water Quality Overview
Maricopa, Arizona receives a water quality grade of C with an overall score of 56 out of 100, based on EPA compliance data from the Safe Drinking Water Information System (SDWIS).
The 5 water systems serving Maricopa have accumulated 288 EPA violations, including 108 health-based violations. These violations are tracked across 4 ZIP codes serving approximately 101,115 people.
What Grade C Means
A grade of C indicates moderate compliance issues. Maricopa'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 Maricopa water systems is 0.0008 mg/L — within EPA limits. No ZIP codes exceed the EPA lead action level.
Radon Risk
Maricopa is in EPA Radon Zone 2 (Moderate risk). Testing is recommended, especially for homes with basements or ground-level living spaces.
Water Systems Serving Maricopa
Maricopa is served by 5 community water systems regulated under the Safe Drinking Water Act. These systems collectively serve approximately 101,115 people across 4 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 40 enforcement actions against water systems serving Maricopa. Enforcement actions range from informal compliance assistance to formal orders and penalties.
How to Check Your Water in Maricopa
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 Maricopa Water Systems
The following contaminants have been detected or caused violations across Maricopa's water systems:
| Contaminant | Category | MCL | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|---|
| Lead | Inorganic | 0.015 mg/L | 88 | 4 | Yes |
| Revised Total Coliform Rule | Microbiological | N/A | 40 | 4 | No |
| Lead and Copper Rule | Treatment Technique | N/A | 32 | 4 | No |
| Surface Water Treatment Rule | Treatment Technique | N/A | 16 | 4 | No |
| Combined Radium | Radionuclides | 5 pCi/L | 16 | 4 | Yes |
| Barium | Inorganic | 2 mg/L | 12 | 4 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 0.08 mg/L | 8 | 4 | No |
| Stage 2 DBP Rule | Treatment Technique | N/A | 8 | 4 | Yes |
| Radium-226 | Radionuclides | 5 pCi/L | 4 | 4 | No |
| Radium-228 | Radionuclides | 5 pCi/L | 4 | 4 | No |
| Stage 1 DBP Rule | Treatment Technique | N/A | 4 | 4 | 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 10 enforcement actions against water systems serving Maricopa. Recent actions:
| Date | Action Type |
|---|---|
| 2025-09-22 | State Order Extension |
| 2025-09-09 | State Informal Action |
| 2025-09-09 | State Informal Enforcement |
| 2025-09-05 | State Informal Action |
| 2025-09-04 | State Informal Action |
| 2025-08-28 | State Formal Action |
| 2025-08-28 | State Informal Action |
| 2025-08-28 | State Informal Enforcement |
| 2024-12-09 | State Order Extension |
| 2024-11-29 | State Informal Action |
Enforcement actions range from informal compliance assistance to formal orders and penalties. The most recent action was on 2025-09-22.
Maricopa vs. Nearby Arizona Cities
How Maricopa's water quality compares to similar cities in Arizona:
| City | Grade | Violations | Systems | Population |
|---|---|---|---|---|
| Maricopa | C | 288 | 5 | 101,115 |
| San Tan Valley | C | 62 | 4 | 98,772 |
| Queen Creek | B | 105 | 3 | 97,812 |
| Flagstaff | C | 120 | 5 | 92,709 |
Water Quality by ZIP Code in Maricopa
Water quality varies across Maricopa's ZIP codes. The table below shows the worst-scoring and best-scoring areas:
| ZIP Code | Score | Grade | Violations | Health-Based |
|---|---|---|---|---|
| 85238 | 50 | D | 72 | 27 |
| 85138 | 58 | C | 72 | 27 |
| 85139 | 58 | C | 72 | 27 |
| 85239 | 58 | C | 72 | 27 |
Common Questions About Maricopa Water
These are the most common questions residents search for about water quality in Maricopa, Arizona:
Is Maricopa water hard or soft? Water hardness varies by source. Maricopa's 5 water systems use multiple sources. Check your ZIP code report for specific hardness data.
Can I drink Maricopa tap water? Maricopa's water receives a grade of C (56/100). There are 108 health-based violations — consider filtration.
What is the best water filter for Maricopa? A NSF/ANSI 53-certified filter for lead removal is a good general choice. See our Water Filter Matcher for personalized recommendations.
Maricopa vs. Arizona Average
Understanding how Maricopa 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 Maricopa.
ZIP Codes in Maricopa
Maricopa spans 4 ZIP codes. The ZIP with the lowest water quality score is 85138. 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.