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County water report

Coconino County Water Report

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

Water grade

F

Water score

33.6

State rank

#6

of 15

Health violations

83

EPA SDWIS, 5-year lookback

Watershed impaired

8.1%

111 water bodies assessed

Monitoring sites

267

70,225 recent measurements

Live streamflow

166%

COLORADO R ABV NATIONAL CANYON NR SUPAI

Water at a glance

Key Water Indicators for Coconino County

EPA SDWIS

Safety Grade

F

Score: 33.6 / 100

EPA SDWIS

Active Violations

83

5-year health-based lookback

EPA ATTAINS

Watershed Health

8% impaired

111 bodies assessed

USGS NWIS

Streamflow Snapshot

166% of mean

COLORADO R ABV NATIONAL CANYON NR SUPAI

EPA WQP

Monitoring Sites

267

70,225 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.

33.6/100

Health violations

83

Health-based violations

Violations per 100K served

51.7

Population-normalized SDWIS rate

Editorial analysis

Understanding Coconino County’s Water

Drinking Water Quality Overview

EPA SDWIS

Coconino County's water systems carry a failing grade, scoring 33.6 out of 100. Over the past five years, EPA SDWIS records 83 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 — 8.1% — of assessed waterways are impaired (9 of 111 water bodies) across Coconino County's watersheds. The leading impairment causes are copper and ph. 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 1996-04-25T23:45:00.000-07:00) puts COLORADO R ABV NATIONAL CANYON at 19.6k cfs — running significantly above its long-term average at 166% of mean flow. 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. Coconino County has extensive coverage with 267 active monitoring sites with 70,225 recent measurements on record. Predominant monitoring categories include physical and inorganics, minor, metals. 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 Coconino County

Water Verdict

Coconino County, Arizona receives a poor water quality assessment with a grade of F and a score of 33.6 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 111 water bodies in the county's watershed, with 8.1% 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 running above its historical mean at 166.1%.

Violation Context

EPA SDWIS records for Coconino County, Arizona show 83 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 51.7 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: 70,225 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Coconino County has a Grade F compliance record with 83 health-based violations — among the highest levels in the country. Coconino County's drinking-water compliance score is 33.6 out of 100. The violation rate for Coconino County is 51.7 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. Copper is the leading impairment cause in Coconino County's watershed. With 267 active water-quality monitoring sites in Coconino County, data coverage is strong. A pipeline streamflow snapshot from the COLORADO R ABV NATIONAL CANYON gauge is also available on this page.

Regional Context

Coconino County has water quality close to the average county in Arizona. Its water score is within 5 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 Coconino County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Copper

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

  • 2

    pH imbalance

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

  • 3

    Mercury (fish tissue)

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Coconino County

EPA How's My Waterway

Interactive watershed health data for Coconino County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Coconino County

Consumer Confidence Reports (AZ)

Annual water quality reports from utilities in Arizona

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

8.1%

9 of 111 assessed

Mostly healthy

Top Impairment Causes

  • 1

    COPPER

  • 2

    PH

  • 3

    MERCURY IN FISH TISSUE

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

267

Active in the past 5 years

Measurements Recorded

70K

70,225 total readings

Most Measured

  • Physical
  • Inorganics, Minor, Metals
  • Organics, Pesticide

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

19.6Kcfs

Apr 26, 6:45 AM UTC

vs Long-Term Average

166%

Well above typical

Primary Streamgage

COLORADO R ABV NATIONAL CANYON NR SUPAI

USGS site
09404120
Drainage area
147,931 sq mi
Long-term mean
11.8K 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 Coconino 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 Coconino County, Arizona?
Coconino County, Arizona has a drinking-water quality grade of F with a score of 33.6/100, based on EPA SDWIS compliance data. The county has 83 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 Coconino County?
Coconino County has 83 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 Coconino County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 8.1% of Coconino County's 111 assessed water bodies are classified as impaired (9 impaired). The top reported causes are COPPER, PH, MERCURY IN FISH TISSUE. 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 Coconino County?
EPA's Water Quality Portal records 70,225 measurements from 267 monitoring sites in Coconino County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, Metals, Organics, Pesticide. 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 Coconino County right now?
Coconino County's primary USGS streamgage on the COLORADO R ABV NATIONAL CANYON has a pipeline snapshot of 19,600 cubic feet per second — 166% of the long-term mean of 11,796.67 cfs. This is well above typical — often a signal of recent precipitation or storm runoff. For the latest gauge feed, visit waterdata.usgs.gov.
How does Coconino County water compare to the Arizona average?
Coconino County's SDWIS water quality score of 33.6/100 is higher 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 Coconino County?
Based on EPA SDWIS data, Coconino County has a water quality grade of F (33.6/100). 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 Coconino County have so many water violations?
Coconino County has 83 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 Coconino County rank for water quality in Arizona?
Coconino County ranks #6 out of 15 counties in Arizona by SDWIS water quality score (1 = best). With a score of 33.6/100, 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

Apache County

Arizona

F

34.3

Water score

Santa Cruz County

Arizona

F

34.5

Water score

Pinal County

Arizona

F

30.4

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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