waterbycounty
Compiled federal source snapshot

Arizona Water Quality

Drinking water data for all 15 counties.

Avg SDWIS Compliance Index

27.0

Most Common Five-Year SDWIS Compliance Band

F

Counties with Data

15

of 15 total

County water atlas

Arizona water signals by county

A state-level 2.5D view across drinking-water compliance, watershed impairment, monitoring density, and streamflow snapshot context. Pin any county, switch layers, then use the lens controls to compare index ranges, recorded violation rates, or impaired watersheds without leaving the page.

Counties

15

Avg SDWIS index

27.0

Watersheds

15

ATTAINS counties

Monitoring

15

13 fresh USGS snapshots

State atlas layers combine EPA SDWIS health-based violations, EPA ATTAINS 303(d) impairment assessments, EPA Water Quality Portal monitoring sites, and representative USGS NWIS streamflow gauges. Streamflow values appear only for fresh pipeline snapshots, not as a continuously updated stream. County pages include the observation time and year.

Prepared by ByCounty Editorial TeamPublished by WaterByCounty

Multi-source coverage in Arizona

Beyond Drinking Water

EPA SDWIS

15/ 15

counties with drinking-water compliance data

951 health violations statewide (5yr)

EPA ATTAINS

28.2%

avg impaired across 15 counties

82 of 291 assessed bodies impaired

EPA WQP

5,337

monitoring sites across 15 counties

1,155,315 total readings (5yr window)

USGS NWIS

13

counties with a fresh pipeline snapshot

2 above10 below

State atlas notes

What stands out in Arizona

County water quality is not one number. The strongest read comes from comparing drinking-water compliance against watershed impairment, monitoring density, and streamflow context. Use these signals as a starting point, then open any county profile for source-level detail.

Compliance spread

Maricopa County has the highest value in the published state SDWIS Compliance Index table at 68.2/100, while Greenlee County has the lowest at 5.9/100. That is a 62.3 point gap inside one state.

Zero health violations

0

3+ health violations

15

Watershed pressure

The atlas impairment layer points to counties where assessed water bodies are most likely to miss state quality standards. Assessment density varies, so compare the percentage with the number of assessed bodies on the county page.

Santa Cruz County66.7%Cochise County63.6%Pinal County50.0%

Monitoring hubs

Maricopa County2,147 sitesYavapai County825 sitesPima County646 sites

Lowest flow reads

Apache County0%La Paz County0%Maricopa County0%

Highest fresh streamflow pipeline snapshots: Santa Cruz County (1888%, observation 2026), Cochise County (1052%, observation 2026), Greenlee County (92%, observation 2026). These are source-data observations, not household tap-water conclusions.

All Arizona Counties

CountySDWIS Compliance Index
Maricopa County68.2
Pima County61.0
Pinal County32.0
Coconino County31.9
Mohave County29.8
Graham County28.0
Santa Cruz County26.4
Apache County25.1
Navajo County21.8
Cochise County19.1
Yavapai County17.5
Yuma County15.7
Gila County14.5
La Paz County7.6
Greenlee County5.9

Frequently Asked Questions

Which Arizona county has the highest SDWIS Compliance Index?
Maricopa County has the highest SDWIS Compliance Index in the published Arizona cohort at 68.2/100. This WaterByCounty relative comparison is not an EPA score and does not establish current conditions for a utility or address.
What does the Five-Year SDWIS Compliance Band mean?
The band is derived only from each county aggregation's recorded health-violation rate per 100,000 people served for the stated five-year source window. It is separate from the relative SDWIS Compliance Index and is not a current determination for a specific utility or address.
What does EPA ATTAINS report across Arizona?
Across 15 published Arizona county records with EPA ATTAINS data, 82 of 291 assessed water bodies are listed as impaired. This is a watershed assessment and does not describe finished household tap water.
Which USGS streamflow records are shown across Arizona?
WaterByCounty has 13 fresh USGS pipeline snapshots in the published Arizona cohort. Each county page shows its observation timestamp and year. A pipeline snapshot is not a continuously updated reading or a tap-water safety measure.
Where can Arizona residents find current official information?
Review the applicable utility's Consumer Confidence Report, active notices, and the state drinking-water agency. WaterByCounty's county-level historical aggregations do not establish the current status of a specific utility, address, private well, or household plumbing system.
What does Water Quality Portal monitoring volume show in Arizona?
The published county records contain 1,155,315 results from 5,337 monitoring locations in the site's five-year aggregation. Monitoring volume does not by itself indicate better or worse water quality.

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. The WaterByCounty SDWIS Compliance Index reflects the recorded rate and is not an EPA score.

Disclaimer: This data is informational only. It is not health, legal, or professional advice. For concerns about your specific water supply, contact your local water utility.

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