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County water report

Mohave County Water Report

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

Water grade

F

Water score

26.2

State rank

#8

of 15

Health violations

184

EPA SDWIS, 5-year lookback

Watershed impaired

3.3%

30 water bodies assessed

Monitoring sites

141

33,713 recent measurements

Live streamflow

56%

COLORADO RVR ABV DIAMOND CREEK NR PEACH SPRINGS AZ

Water at a glance

Key Water Indicators for Mohave County

EPA SDWIS

Safety Grade

F

Score: 26.2 / 100

EPA SDWIS

Active Violations

184

5-year health-based lookback

EPA ATTAINS

Watershed Health

3% impaired

30 bodies assessed

USGS NWIS

Streamflow Snapshot

56% of mean

COLORADO RVR ABV DIAMOND CREEK NR PEACH SPRINGS AZ

EPA WQP

Monitoring Sites

141

33,713 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.

26.2/100

Health violations

184

Health-based violations

Violations per 100K served

84.2

Population-normalized SDWIS rate

Editorial analysis

Understanding Mohave County’s Water

Drinking Water Quality Overview

EPA SDWIS

Mohave County's water systems carry a failing grade, scoring 26.2 out of 100. Over the past five years, EPA SDWIS records 184 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 — 3.3% — of assessed waterways are impaired (1 of 30 water bodies) across Mohave County's watersheds. The leading impairment cause is ammonia-nitrogen. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T11:30:00.000-07:00) puts COLORADO RVR ABV DIAMOND CREEK at 7.5k cfs — well below its long-term average at 56% of mean — low-flow conditions worth noting for water-dependent ecosystems. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Mohave County has extensive coverage with 141 active monitoring sites with 33,713 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 Mohave County

Water Verdict

Mohave County, Arizona receives a poor water quality assessment with a grade of F and a score of 26.2 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. Separately, EPA ATTAINS assessments cover 30 water bodies in the county's watershed, with 3.3% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance. At the most recent USGS reading, local streamflow was below its historical mean at 55.5% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Mohave County, Arizona show 184 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 84.2 violations per 100,000 people served, this rate is high and signals significant water quality management issues. This compliance record sits alongside an unusually deep monitoring archive: 33,713 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Mohave County has a Grade F compliance record with 184 health-based violations — among the highest levels in the country. Mohave County's drinking-water compliance score is 26.2 out of 100. The violation rate for Mohave County is 84.2 per 100,000 people served. 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. Ammonia-Nitrogen is the leading impairment cause in Mohave County's watershed. With 141 active water-quality monitoring sites in Mohave County, data coverage is strong. A pipeline streamflow snapshot from the COLORADO RVR ABV DIAMOND CREEK gauge is also available on this page.

Regional Context

Mohave County has water quality close to the average county in Arizona. Its water score is within 2.4 points of the state average, meaning its overall water system performance is broadly representative of Arizona as a whole.

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 Mohave County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Ammonia-Nitrogen

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Mohave County

EPA How's My Waterway

Interactive watershed health data for Mohave County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Mohave County

Consumer Confidence Reports (AZ)

Annual water quality reports from utilities in Arizona

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

3.3%

1 of 30 assessed

Mostly healthy

Top Impairment Causes

  • 1

    AMMONIA-NITROGEN

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

141

Active in the past 5 years

Measurements Recorded

34K

33,713 total readings

Most Measured

  • Organics, Other
  • Organics, Pesticide
  • Inorganics, Minor, Metals

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).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

7,510cfs

May 14, 6:30 PM UTC

vs Long-Term Average

56%

Well below typical

Primary Streamgage

COLORADO RVR ABV DIAMOND CREEK NR PEACH SPRINGS AZ

USGS site
09404200
Drainage area
149,316 sq mi
Long-term mean
13.5K cfs

One representative streamgage (the one with the largest drainage area in the county). Many counties have multiple gauges; this view summarizes the primary one. The long-term mean is the full-record annual average; the percent-of-typical value compares the latest reading against that average.

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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 Mohave 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.

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Frequently Asked Questions

What is the water quality in Mohave County, Arizona?
Mohave County, Arizona has a drinking-water quality grade of F with a score of 26.2/100, based on EPA SDWIS compliance data. The county has 184 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 Mohave County?
Mohave County has 184 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 Mohave County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 3.3% of Mohave County's 30 assessed water bodies are classified as impaired (1 impaired). The top reported causes are AMMONIA-NITROGEN. 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 Mohave County?
EPA's Water Quality Portal records 33,713 measurements from 141 monitoring sites in Mohave County over the past five years. The most frequently measured characteristic groups are Organics, Other, Organics, Pesticide, Inorganics, Minor, Metals. 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.
What's happening with rivers in Mohave County right now?
Mohave County's primary USGS streamgage on the COLORADO RVR ABV DIAMOND CREEK has a pipeline snapshot of 7,510 cubic feet per second — 56% of the long-term mean of 13,525 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Mohave County water compare to the Arizona average?
Mohave County's SDWIS water quality score of 26.2/100 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 Mohave County?
Based on EPA SDWIS data, Mohave County has a water quality grade of F (26.2/100). 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 Mohave County have so many water violations?
Mohave County has 184 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 Mohave County rank for water quality in Arizona?
Mohave County ranks #8 out of 15 counties in Arizona by SDWIS water quality score (1 = best). With a score of 26.2/100, it falls in the middle 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

Navajo County

Arizona

F

24.7

Water score

Pinal County

Arizona

F

30.4

Water score

Cochise County

Arizona

F

21.7

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.

Live streamflow from the USGS National Water Information System (NWIS), continuous discharge measurements from the largest-drainage gauge in each county, compared against the full-record long-term annual mean.

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

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