PlainWater
States → Arizona

State profile · EPA SDWIS + UCMR5

Arizona Drinking Water Quality

1,493 public water systems serve 7,322,166 people across Arizona, with every Safe Drinking Water Act violation and UCMR5 PFAS result on record.

1,493
Water systems
228,944
Total violations
98.4%
Systems w/ a violation
95.4%
PFAS detection rate

The verdict

Across Arizona, 1,469 of 1,493 water systems (98.4%) carry at least one EPA violation, and 145 of 152 UCMR5-tested systems show PFAS.

228,944
Total EPA violations on record
7%
Health-based (MCL / treatment)
98.4%
Systems with ≥1 violation
95.4%
UCMR5 PFAS detection rate
Water Systems
1,493
Total Violations
228,944
Violation Rate
98.4%
PFAS Detection
95.4%
145 of 152 tested

Violation Composition

How Arizona's 228,944 violations break down by type, per EPA SDWIS classification.

Health-based (15,663) Monitoring/Reporting (213,281)
Metric Value Share
Public water systems1,493-
Population served7,322,166-
Total violations228,944100%
Health-based violations15,6636.8%
Systems with violations1,46998.4%
PFAS detection rate145 of 15295.4%

Health-based violations indicate the contaminant exceeded an EPA Maximum Contaminant Level (MCL) or treatment-technique requirement. Monitoring/reporting violations indicate procedural issues (missed tests, late reports) - not necessarily a contamination event.

Largest Water Systems

Phoenix City Of
Phoenix, AZ · 1,695,000 served
84 violations
Tucson City Of
Tucson, AZ · 732,906 served
2,267 violations
Mesa City Of
Mesa, AZ · 466,000 served
1,739 violations
Gilbert, Town Of
Gilbert, AZ · 247,600 served
1,235 violations
Chandler City Of
Chandler, AZ · 247,328 served
851 violations
Scottsdale City Of
Scottsdale, AZ · 241,361 served
963 violations
Glendale City Of
Phoenix, AZ · 234,766 served
645 violations
Peoria City Of
Peoria, AZ · 187,676 served
2,461 violations
Tempe City Of
Tempe, AZ · 165,000 served
339 violations
Arizona Water Co - Pinal Valley
Phoenix, AZ · 134,432 served
590 violations
Epcor - Agua Fria
El Mirage, AZ · 127,718 served
525 violations
City of Yuma
Yuma, AZ · 103,264 served
456 violations
Queen Creek Town Of
Queen Creek, AZ · 95,502 served
494 violations
Epcor - San Tan
San Tan Valley, AZ · 87,435 served
367 violations
Gw Santa Cruz Water Co
Maricopa, AZ · 84,000 served
256 violations
Avondale City Of
Avondale, AZ · 83,001 served
242 violations
Flagstaff City Of
Flagstaff, AZ · 76,960 served
1,061 violations
Arizona Water Co - Apache Junction
Phoenix, AZ · 62,055 served
88 violations
Town of Prescott Valley
Dewey, AZ · 57,048 served
396 violations
Lake Havasu City Of
Lake Havasu City, AZ · 54,610 served
312 violations

Most Violations

#1 Pueblo del Sol Water Company Sierra Vista
2,721
#2 Bullhead City Mohave Bullhead City
2,669
#3 Peoria City Of Peoria
2,461
#4 Tucson City Of Tucson
2,267
#5 Oro Valley Water Utility Oro Valley
2,191
#6 Big Park Water Company Sedona
2,033
#7 Nogales City Of Nogales
1,954
#8 Foothills Water and Sewer LLC Yuma
1,945
#9 Mesa City Of Mesa
1,739
#10 Payson Town Of Payson
1,716
#11 Bella Vista City Water System Sierra Vista
1,564
#12 Bermuda Water Company Inc Fort Mohave
1,469
#13 Mohawk Valley School District Roll
1,438
#14 Antelope Peak Dwid Maricopa
1,243
#15 Gilbert, Town Of Gilbert
1,235

Counties in Arizona

Maricopa
215 systems · 4,392,896 served · 30,745 violations
Pima
195 systems · 1,138,545 served · 30,465 violations
Pinal
94 systems · 505,241 served · 20,790 violations
Mohave
119 systems · 231,271 served · 20,586 violations
Yavapai
238 systems · 223,192 served · 25,793 violations
Yuma
51 systems · 217,720 served · 16,217 violations
Coconino
116 systems · 180,537 served · 13,681 violations
Cochise
104 systems · 129,689 served · 19,234 violations
Navajo
63 systems · 99,221 served · 9,952 violations
Gila
103 systems · 62,233 served · 15,775 violations
Santa Cruz
37 systems · 49,946 served · 6,256 violations
La Paz
83 systems · 30,510 served · 8,301 violations
Graham
16 systems · 29,739 served · 3,328 violations
Apache
47 systems · 23,153 served · 5,592 violations
Greenlee
11 systems · 8,173 served · 2,184 violations
View all 1,493 systems in Arizona →

Drinking Water Guides

Is Your Tap Water Safe?

How to interpret water quality reports and know when to take action.
PFAS in Drinking Water

What forever chemicals are, EPA testing results, and 2024 standards.
Check Your Water System

Step-by-step guide to finding and understanding your local water data.

Frequently Asked Questions

How many water systems are in Arizona? ▼
Arizona has 1,493 public water systems serving approximately 7,322,166 people. These include community water systems, non-transient non-community systems, and transient non-community systems regulated under the Safe Drinking Water Act.
How many drinking water violations are in Arizona? ▼
Arizona has 228,944 total drinking water violations on record, with 15,663 classified as health-based violations. 98.4% of water systems in the state have at least one violation.
Has PFAS been found in Arizona drinking water? ▼
Of 152 water systems tested for PFAS in Arizona, 145 had PFAS detected, a 95.4% detection rate. PFAS are persistent "forever chemicals" that do not break down in the environment.
What is the violation rate for Arizona water systems? ▼
Arizona's violation rate is 98.4%. This measures the percentage of public water systems that have at least one recorded violation in the EPA SDWIS database, including both health-based and monitoring/reporting violations.
Where does this Arizona water data come from? ▼
All drinking water data comes from the EPA Safe Drinking Water Information System (SDWIS) and the UCMR5 PFAS monitoring program. SDWIS is the federal database that tracks compliance for all public water systems regulated under the Safe Drinking Water Act.

Data Sources & Methodology

Drinking water violation data from the EPA Safe Drinking Water Information System (SDWIS). PFAS testing data from the UCMR5 monitoring program. SDWIS tracks all public water systems regulated under the Safe Drinking Water Act.

Read our methodology - how this data is sourced, computed, and verified.

Related

All states → | Most violations → | Compare counties →
Data sourced from EPA SDWIS and UCMR5 PFAS monitoring data. See our methodology for details. Retrieved and formatted by PlainWater Editorial

Every figure on PlainWater is rendered directly from EPA SDWIS drinking-water data, no number is typed in by an editor. This page draws directly on EPA SDWIS data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.