waterbycounty
Federal water data

County water report

Yuma County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Yuma County, Arizona.

Water grade

F

Water score

15.2

State rank

#13

of 15

Health violations

410

EPA SDWIS, 5-year lookback

Watershed impaired

7.7%

26 water bodies assessed

Monitoring sites

207

44,014 recent measurements

Live streamflow

No gauge

COLORADO RIVER AT NIB, ABOVE MORELOS DAM, AZ

Water at a glance

Key Water Indicators for Yuma County

EPA SDWIS

Safety Grade

F

Score: 15.2 / 100

EPA SDWIS

Active Violations

410

5-year health-based lookback

EPA ATTAINS

Watershed Health

8% impaired

26 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

COLORADO RIVER AT NIB, ABOVE MORELOS DAM, AZ

EPA WQP

Monitoring Sites

207

44,014 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

F

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

15.2/100

Health violations

410

Health-based violations

Violations per 100K served

194.8

Population-normalized SDWIS rate

Editorial analysis

Understanding Yuma County’s Water

Drinking Water Quality Overview

EPA SDWIS

Yuma County's water systems carry a failing grade, scoring 15.2 out of 100. Over the past five years, EPA SDWIS records 410 health-based violations — a pattern that public water utilities are required to disclose and correct.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A small share — 7.7% — of assessed waterways are impaired (2 of 26 water bodies) across Yuma County's watersheds. The leading impairment cause is escherichia coli (e. coli). Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Yuma County has extensive coverage with 207 active monitoring sites with 44,014 recent measurements on record. Predominant monitoring categories include organics, other and organics, pesticide. More monitoring sites generally indicate greater scientific attention to local water conditions — and provide the baseline data that regulators use to set future impairment listings.

Editorial advisory

What the data suggests for Yuma County

Water Verdict

Yuma County receives a poor water quality assessment with a grade of F and a score of 15.2 out of 100. The water supply has documented quality issues. Residents are strongly encouraged to use filtered or bottled water for drinking and to stay informed about utility improvement plans.

Violation Context

Yuma County has recorded 410 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 194.8 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Yuma County has a Grade F compliance record with 410 health-based violations — among the highest levels in the country. Yuma County's drinking-water compliance score is 15.2 out of 100. Residents are strongly advised to use a certified NSF 58 reverse-osmosis filter or bottled water for all drinking and cooking until violations are corrected. Contacting the Arizona Department of Environmental Quality or Health can expedite utility compliance action. E. coli is the leading impairment cause in Yuma County's watershed. With 207 active water-quality monitoring sites in Yuma County, data coverage is strong. A pipeline streamflow snapshot from the COLORADO RIVER gauge is also available on this page.

Regional Context

Yuma County has poorer water quality than the average county in Arizona. Its water score is 13.4 points lower than the state average, suggesting more challenges with contamination control or infrastructure than neighboring counties.

Advisory text summarizes county-level public records and is not a replacement for your utility's current Consumer Confidence Report or direct local notices.

Contaminants & Resources

Key issues flagged in Yuma County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    E. coli (bacteria)

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Yuma County

EPA How's My Waterway

Interactive watershed health data for Yuma County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Yuma County

Consumer Confidence Reports (AZ)

Annual water quality reports from utilities in Arizona

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

7.7%

2 of 26 assessed

Mostly healthy

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

Source: EPA ATTAINS · Reporting cycle 2022

Impairment is determined under the Clean Water Act §303(d): a water body is impaired when it fails to meet state-defined quality standards for designated uses (drinking, recreation, aquatic life). Assessment coverage varies by state; counties without assessed water bodies are not shown.

Past 5 years

Water Quality Monitoring

Monitoring Sites

207

Active in the past 5 years

Measurements Recorded

44K

44,014 total readings

Most Measured

  • Organics, Other
  • Organics, Pesticide
  • Physical

Categories measured most frequently

Data from the EPA Water Quality Portal (WQP), aggregating monitoring records from federal, state, and tribal sources. Each measurement represents a single sample analyzed for a specific characteristic (e.g., E. coli, pH, dissolved oxygen, nitrogen).

Free tool

Estimate Your Water Costs

Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Yuma County:C — Moderate

Some violations or watershed impairment detected.

Estimates use the national average residential water rate ($0.0068/gal, EPA/AWWA 2023) and EPA WaterSense per-person consumption baseline (75 gal/person/day). Actual bills vary by utility, usage tier, and local infrastructure fees. For informational purposes only.

Try the full calculator →

Improve your water quality at home

Berkey filters remove 99.9%+ of contaminants from tap water.

Shop Berkey →

Sponsored

Test your tap water

Tap Score provides professional mail-in water testing.

Get Tested →

Frequently Asked Questions

What is the water quality in Yuma County, Arizona?
Yuma County, Arizona has a drinking-water quality grade of F with a score of 15.2/100, based on EPA SDWIS compliance data. The county has 410 health-based drinking water violations over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Yuma County?
Yuma County has 410 health-based drinking water violations recorded by the EPA over the past 5 years. Health-based violations indicate instances where contaminant levels exceeded EPA Maximum Contaminant Levels (MCLs). Violations may have been resolved — check with your local water utility for current status.
How healthy are the watersheds in Yuma County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 7.7% of Yuma County's 26 assessed water bodies are classified as impaired (2 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI). Impairment means the water body fails to meet state quality standards for at least one designated use — drinking water source, recreation, aquatic life, or fish consumption. Note: watershed impairment doesn't always translate to tap-water issues; treatment plants can remove most regulated contaminants.
How much water-quality monitoring happens in Yuma County?
EPA's Water Quality Portal records 44,014 measurements from 207 monitoring sites in Yuma County over the past five years. The most frequently measured characteristic groups are Organics, Other, Organics, Pesticide, Physical. Each measurement is a single sample analyzed for one characteristic (E. coli, pH, dissolved oxygen, etc.). High monitoring density means more scientific evidence behind any reported signal — it does not by itself indicate water quality.
How does Yuma County water compare to the Arizona average?
Yuma County's SDWIS water quality score of 15.2/100 is lower than the Arizona state average of 28.6. The average water quality grade across Arizona is F, based on data from 15 counties with available SDWIS data.
Is tap water safe to drink in Yuma County?
Based on EPA SDWIS data, Yuma County has a water quality grade of F (15.2/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. The grade speaks to the public water system, not the watershed — for watershed-level concerns, see the Watershed Health zone. For the most up-to-date information, contact your local water utility or review your Consumer Confidence Report (CCR).
Why does Yuma County have so many water violations?
Yuma County has 410 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.
How does Yuma County rank for water quality in Arizona?
Yuma County ranks #13 out of 15 counties in Arizona by SDWIS water quality score (1 = best). With a score of 15.2/100, it falls in the bottom third of counties statewide. The ranking reflects EPA SDWIS compliance only — not watershed impairment, monitoring density, or streamflow, which are tracked separately on this page.

Counties with Similar Water Quality

Gila County

Arizona

F

16.6

Water score

Yavapai County

Arizona

F

18.6

Water score

La Paz County

Arizona

F

9.8

Water score

Data Sources

Drinking-water compliance data from the EPA Safe Drinking Water Information System (SDWIS) via the ECHO enforcement database. Scores reflect compliance history and health-based violation counts.

Watershed health and impaired-waterway data from the EPA ATTAINS Clean Water Act §303(d) assessments, state-reported and EPA-finalized.

Water-quality monitoring counts from the EPA Water Quality Portal (WQP), federated USGS, EPA, and state agency sampling records over a rolling 5-year window.

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.

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Explore more data for Yuma County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsDisaster RiskWeatherCounty Score