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Federal water data

County water report

Owyhee County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Owyhee County, Idaho.

Water grade

F

Water score

19.8

State rank

#23

of 44

Health violations

7

EPA SDWIS, 5-year lookback

Watershed impaired

35.8%

492 water bodies assessed

Monitoring sites

43

4,700 recent measurements

Live streamflow

67%

SNAKE RIVER BL CJ STRIKE DAM NR GRAND VIEW ID

Water at a glance

Key Water Indicators for Owyhee County

EPA SDWIS

Safety Grade

F

Score: 19.8 / 100

EPA SDWIS

Active Violations

7

5-year health-based lookback

EPA ATTAINS

Watershed Health

36% impaired

492 bodies assessed

USGS NWIS

Streamflow Snapshot

67% of mean

SNAKE RIVER BL CJ STRIKE DAM NR GRAND VIEW ID

EPA WQP

Monitoring Sites

43

4,700 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.

19.8/100

Health violations

7

Health-based violations

Violations per 100K served

133.9

Population-normalized SDWIS rate

Editorial analysis

Understanding Owyhee County’s Water

Drinking Water Quality Overview

EPA SDWIS

Owyhee County's water systems carry a failing grade, scoring 19.8 out of 100. Over the past five years, EPA SDWIS records 7 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 substantial 35.8% of assessed waterways are impaired (176 of 492 water bodies) across Owyhee County's watersheds. The leading impairment causes are temperature and sedimentation/siltation. 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 2001-04-11T23:45:00.000-06:00) puts SNAKE RIVER BL CJ STRIKE DAM at 5.9k cfs — running somewhat below its historical average at 67% of mean. 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. Owyhee County has moderate coverage with 43 active monitoring sites with 4,700 recent measurements on record. Predominant monitoring categories include physical and biological, fish. 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 Owyhee County

Water Verdict

Owyhee County receives a poor water quality assessment with a grade of F and a score of 19.8 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

Owyhee County has recorded 7 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 133.9 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Drinking-water compliance in Owyhee County is rated Grade F, reflecting significant health-based violations in the recent reporting period. Owyhee County's drinking-water compliance score is 19.8 out of 100. An NSF 53 or NSF 58-certified filter is recommended for drinking and cooking water. Check the Consumer Confidence Report from your utility to identify the specific contaminants and required corrective actions — utilities are legally required to notify customers of violations. Temperature is the leading impairment cause in Owyhee County's watershed. With 43 active water-quality monitoring sites in Owyhee County, data coverage is strong. A pipeline streamflow snapshot from the SNAKE RIVER BL CJ STRIKE DAM gauge is also available on this page.

Regional Context

Owyhee County has poorer water quality than the average county in Idaho. Its water score is 12.8 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 Owyhee County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Elevated temperature

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

  • 2

    Sedimentation and siltation

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

  • 3

    Flow Regime Modification

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Owyhee County

EPA How's My Waterway

Interactive watershed health data for Owyhee County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Owyhee County

Consumer Confidence Reports (ID)

Annual water quality reports from utilities in Idaho

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

35.8%

176 of 492 assessed

Moderate concern

Top Impairment Causes

  • 1

    TEMPERATURE

  • 2

    SEDIMENTATION/SILTATION

  • 3

    FLOW REGIME MODIFICATION

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

43

Active in the past 5 years

Measurements Recorded

4.7K

4,700 total readings

Most Measured

  • Physical
  • Biological, Fish
  • 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

5,910cfs

Apr 12, 5:45 AM UTC

vs Long-Term Average

67%

Below typical

Primary Streamgage

SNAKE RIVER BL CJ STRIKE DAM NR GRAND VIEW ID

USGS site
13171620
Drainage area
40,800 sq mi
Long-term mean
8,836 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.

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 Owyhee 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 Owyhee County, Idaho?
Owyhee County, Idaho has a drinking-water quality grade of F with a score of 19.8/100, based on EPA SDWIS compliance data. The county has 7 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 Owyhee County?
Owyhee County has 7 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 Owyhee County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 35.8% of Owyhee County's 492 assessed water bodies are classified as impaired (176 impaired). The top reported causes are TEMPERATURE, SEDIMENTATION/SILTATION, FLOW REGIME MODIFICATION. 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 Owyhee County?
EPA's Water Quality Portal records 4,700 measurements from 43 monitoring sites in Owyhee County over the past five years. The most frequently measured characteristic groups are Physical, Biological, Fish, 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 Owyhee County right now?
Owyhee County's primary USGS streamgage on the SNAKE RIVER BL CJ STRIKE DAM has a pipeline snapshot of 5,910 cubic feet per second — 67% of the long-term mean of 8,835.85 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Owyhee County water compare to the Idaho average?
Owyhee County's SDWIS water quality score of 19.8/100 is lower than the Idaho state average of 32.6. The average water quality grade across Idaho is F, based on data from 44 counties with available SDWIS data.
Is tap water safe to drink in Owyhee County?
Based on EPA SDWIS data, Owyhee County has a water quality grade of F (19.8/100). 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 Owyhee County have so many water violations?
Owyhee County has 7 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 Owyhee County rank for water quality in Idaho?
Owyhee County ranks #23 out of 44 counties in Idaho by SDWIS water quality score (1 = best). With a score of 19.8/100, 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

Bonner County

Idaho

F

19.7

Water score

Butte County

Idaho

F

18.7

Water score

Blaine County

Idaho

F

18.1

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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