Arizona Water Quality Report: 29,686 Violations Across 553 ZIPs
584 water systems · 553 ZIP codes · 29,686 violations · Updated 2026-05-31
Data: EPA Safe Drinking Water Information System (SDWIS), EPA ECHO Last verified: 2026-05-31
City Water Quality Map: Arizona
Each circle represents a city. Size indicates population, color indicates water quality grade. Tap a circle for details.
Violation Trend
EPA violations across all water systems in Arizona.
Cities with Most Violations in Arizona
| # | City | Grade | Violations | Systems | Population | |
|---|---|---|---|---|---|---|
| 1 | Tucson | D | 11,772 | 5 | 830,616 | Details → |
| 2 | Phoenix | D | 9,828 | 5 | 2,146,253 | Details → |
| 3 | Glendale | C | 816 | 5 | 245,461 | Details → |
| 4 | Yuma | C | 360 | 5 | 152,412 | Details → |
| 5 | Gilbert | B | 357 | 5 | 248,286 | Details → |
| 6 | Scottsdale | B | 315 | 5 | 242,690 | Details → |
| 7 | Prescott | F | 294 | 5 | 48,456 | Details → |
| 8 | Maricopa | C | 288 | 5 | 101,115 | Details → |
| 9 | Apache Junction | B | 204 | 4 | 77,938 | Details → |
| 10 | Tempe | B | 192 | 4 | 166,887 | Details → |
Most Common Contaminants in Arizona
| Contaminant | Category | Violations | ZIPs Affected | Health Risk |
|---|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | 3,109 | 367 | No |
| Lead and Copper Rule | Treatment Technique | 2,821 | 328 | No |
| Stage 2 DBP Rule | Treatment Technique | 2,213 | 267 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 1,751 | 344 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 1,667 | 325 | No |
| E. coli | Microbiological | 1,585 | 227 | No |
| Fecal Coliform | Microbiological | 1,530 | 167 | Yes |
| Lead | Inorganic | 1,334 | 259 | Yes |
| Barium | Inorganic | 1,233 | 268 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1,163 | 301 | No |
Water Quality Overview
Arizona has 584 community water systems serving approximately 12,157,616 people across 553 ZIP codes. These systems have accumulated 29,686 EPA violations, including 4,074 health-based violations.
Health-based violations account for 14% of all violations in Arizona. These violations indicate contaminant levels that may pose direct risks to human health, as opposed to monitoring or reporting failures.
Violation Breakdown
| Violation Type | Count | Percentage |
|---|---|---|
| Health-based | 4,074 | 13.7% |
| Monitoring/Reporting | 25,612 | 86.3% |
| Total | 29,686 | 100% |
Health-based violations indicate contaminant levels exceeding EPA Maximum Contaminant Levels (MCLs). Monitoring violations indicate failures to test or report — these do not necessarily mean unsafe water, but they mean the water was not properly verified.
Cities with Most Violations
The following cities in Arizona have the highest number of EPA violations:
| Rank | City | Grade | Violations | Water Systems | Population |
|---|---|---|---|---|---|
| 1 | Tucson | D | 11,772 | 5 | 830,616 |
| 2 | Phoenix | D | 9,828 | 5 | 2,146,253 |
| 3 | Glendale | C | 816 | 5 | 245,461 |
| 4 | Yuma | C | 360 | 5 | 152,412 |
| 5 | Gilbert | B | 357 | 5 | 248,286 |
| 6 | Scottsdale | B | 315 | 5 | 242,690 |
| 7 | Prescott | F | 294 | 5 | 48,456 |
| 8 | Maricopa | C | 288 | 5 | 101,115 |
| 9 | Apache Junction | B | 204 | 4 | 77,938 |
| 10 | Tempe | B | 192 | 4 | 166,887 |
Violation counts are cumulative across all water systems serving each city. Higher counts may reflect larger systems with more monitoring requirements, not necessarily worse water quality.
Violation Trend Over Time
Year-by-year EPA violations recorded across all water systems in Arizona:
| Year | Total Violations | Health-Based |
|---|---|---|
| 2021 | 128 | 83 |
| 2022 | 193 | 178 |
| 2023 | 129 | 129 |
| 2024 | 731 | 731 |
| 2025 | 201 | 201 |
Violations have increased from 128 in 2021 to 201 in 2025. This trend warrants monitoring and may reflect expanded testing requirements rather than worsening quality.
Most Common Contaminants
The following contaminants have caused the most violations across Arizona water systems:
| Contaminant | Category | Violations | ZIPs Affected | Health-Based |
|---|---|---|---|---|
| Revised Total Coliform Rule | Microbiological | 3,109 | 367 | No |
| Lead and Copper Rule | Treatment Technique | 2,821 | 328 | No |
| Stage 2 DBP Rule | Treatment Technique | 2,213 | 267 | Yes |
| Stage 1 DBP Rule | Treatment Technique | 1,751 | 344 | Yes |
| Surface Water Treatment Rule | Treatment Technique | 1,667 | 325 | No |
| E. coli | Microbiological | 1,585 | 227 | No |
| Fecal Coliform | Microbiological | 1,530 | 167 | Yes |
| Lead | Inorganic | 1,334 | 259 | Yes |
| Barium | Inorganic | 1,233 | 268 | Yes |
| Total Trihalomethanes (TTHM) | Disinfection Byproducts | 1,163 | 301 | No |
How to Check Your Water in Arizona
Enter your ZIP code on ZipCheckup for detailed water system data including contaminant levels, violation history, and safety scores
Request your CCR — every water utility must provide an annual Consumer Confidence Report
Get a home test — certified kits ($20-$50) or professional lab tests ($150-$400)
Consider filtration — NSF-certified filters can address specific contaminants found in your area
EPA Enforcement
The EPA and state regulators have taken 5,339 enforcement actions against water systems in Arizona. Enforcement actions range from compliance assistance to formal orders and penalties.
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Enforcement: EPA ECHO
Updated daily.
What are EPA violations?
Health-based violations mean a contaminant was detected above the EPA's Maximum Contaminant Level (MCL) — the legal limit designed to protect human health. Arizona has 4,074 such violations across its water systems. Not all violations cause illness, but repeated exceedances increase risk, especially for children and immunocompromised individuals.
Understanding water quality grades
ZipCheckup grades water systems from A to F based on EPA violation history, contaminant levels, and system compliance. Grade A means few or no violations; Grade F indicates persistent or serious issues. Grades are calculated per ZIP code and aggregated at the city, county, and state level.
Wondering about your tap water?
Water quality varies by ZIP code. Enter yours to see contaminant data, violations, and filtration recommendations specific to your area.
Check Your ZIP Code Water Quality →Frequently Asked Questions
Is the tap water safe to drink in Arizona?
Arizona has 584 community water systems with 29,686 recorded EPA violations, including 4,074 health-based. Water quality varies by city and ZIP code — check your specific location for detailed results.
How many water violations does Arizona have?
Arizona has 29,686 total EPA violations across 553 ZIP codes. 4,074 are health-based violations that indicate contaminant levels potentially harmful to human health. The remainder are monitoring or reporting violations.
Which city in Arizona has the worst water quality?
Tucson, AZ has the most EPA violations among major cities in Arizona with 11772 recorded violations. Check individual ZIP codes for the most accurate picture of your local water quality.
Which city in Arizona has the best water quality?
Several cities in Arizona maintain excellent EPA compliance. Check individual city reports for details.
What contaminants are found in Arizona drinking water?
Arizona water systems are monitored for over 90 EPA-regulated contaminants including lead, copper, nitrates, disinfection byproducts, and bacteria. The most common violations vary by region — check your ZIP code for contaminant-specific data.