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County water report

Jerome County Water Report

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

Water grade

D

Water score

47.6

State rank

#13

of 44

Health violations

3

EPA SDWIS, 5-year lookback

Watershed impaired

49.4%

170 water bodies assessed

Monitoring sites

25

1,519 recent measurements

Live streamflow

79%

DEVILS WASHBOWL SPRING NR KIMBERLY 10S 18E 04AAD1S

Water at a glance

Key Water Indicators for Jerome County

EPA SDWIS

Safety Grade

D

Score: 47.6 / 100

EPA SDWIS

Active Violations

3

5-year health-based lookback

EPA ATTAINS

Watershed Health

49% impaired

170 bodies assessed

USGS NWIS

Streamflow Snapshot

79% of mean

DEVILS WASHBOWL SPRING NR KIMBERLY 10S 18E 04AAD1S

EPA WQP

Monitoring Sites

25

1,519 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

D

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

47.6/100

Health violations

3

Health-based violations

Violations per 100K served

19.9

Population-normalized SDWIS rate

Editorial analysis

Understanding Jerome County’s Water

Drinking Water Quality Overview

EPA SDWIS

Jerome County's drinking water received a D grade, scoring 47.6 out of 100. Over the past five years, EPA SDWIS records 3 health-based violations — a small cluster that warrants attention.

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 49.4% of assessed waterways are impaired (84 of 170 water bodies) across Jerome County's watersheds. The leading impairment causes are phosphorus, total and total suspended solids (tss). 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 2026-05-14T12:30:00.000-06:00) puts DEVILS WASHBOWL SPRING at 8.6 cfs — running somewhat below its historical average at 79% 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. Jerome County has moderate coverage with 25 active monitoring sites with 1,519 recent measurements on record. Predominant monitoring categories include organics, pesticide and physical. 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 Jerome County

Water Verdict

Jerome County, Idaho receives a below-average water quality assessment with a grade of D and a score of 47.6 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking. Separately, EPA ATTAINS assessments cover 170 water bodies in the county's watershed, with 49.4% 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 79.1% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Jerome County, Idaho show 3 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 19.9 violations per 100,000 people served, this rate is high and signals significant water quality management issues. For independent context, 1,519 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Jerome County's drinking-water compliance is below average with a Grade D, indicating repeated or unresolved violations in the recent record. Jerome County's drinking-water compliance score is 47.6 out of 100. The violation rate for Jerome County is 19.9 per 100,000 people served. Residents are encouraged to use an NSF 53 or NSF 58-certified filter for drinking and cooking water until the underlying violations are resolved. Running tap water for 30 seconds before use and avoiding older lead-pipe connections can also reduce exposure risk. The current Consumer Confidence Report from your utility will specify the contaminants of concern. Phosphorus, Total is the leading impairment cause in Jerome County's watershed. With 25 active water-quality monitoring sites in Jerome County, data coverage is strong. A pipeline streamflow snapshot from the DEVILS WASHBOWL SPRING gauge is also available on this page.

Regional Context

Jerome County has better water quality than the average county in Idaho. Its water score is 15 points higher than the state average, indicating stronger water system performance relative to 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 Jerome County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Phosphorus (excess nutrients)

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

  • 2

    Total Suspended Solids (Tss)

    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 Jerome County

EPA How's My Waterway

Interactive watershed health data for Jerome County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Jerome County

Consumer Confidence Reports (ID)

Annual water quality reports from utilities in Idaho

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

49.4%

84 of 170 assessed

Moderate concern

Top Impairment Causes

  • 1

    PHOSPHORUS, TOTAL

  • 2

    TOTAL SUSPENDED SOLIDS (TSS)

  • 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

25

Active in the past 5 years

Measurements Recorded

1.5K

1,519 total readings

Most Measured

  • Organics, Pesticide
  • Physical
  • Nutrient

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

8.56cfs

May 14, 6:30 PM UTC

vs Long-Term Average

79%

Below typical

Primary Streamgage

DEVILS WASHBOWL SPRING NR KIMBERLY 10S 18E 04AAD1S

USGS site
13089500
Drainage area
0.22 sq mi
Long-term mean
10.8 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 Jerome 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 Jerome County, Idaho?
Jerome County, Idaho has a drinking-water quality grade of D with a score of 47.6/100, based on EPA SDWIS compliance data. The county has 3 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 Jerome County?
Jerome County has 3 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 Jerome County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 49.4% of Jerome County's 170 assessed water bodies are classified as impaired (84 impaired). The top reported causes are PHOSPHORUS, TOTAL, TOTAL SUSPENDED SOLIDS (TSS), 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 Jerome County?
EPA's Water Quality Portal records 1,519 measurements from 25 monitoring sites in Jerome County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Physical, Nutrient. 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 Jerome County right now?
Jerome County's primary USGS streamgage on the DEVILS WASHBOWL SPRING has a pipeline snapshot of 8.56 cubic feet per second — 79% of the long-term mean of 10.82 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Jerome County water compare to the Idaho average?
Jerome County's SDWIS water quality score of 47.6/100 is higher 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 Jerome County?
Based on EPA SDWIS data, Jerome County has a water quality grade of D (47.6/100). 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).
Does Jerome County have clean drinking water?
Jerome County has 3 health-based drinking water violations according to EPA records. With a water quality score of 47.6/100 and grade D, the county's drinking water has had some compliance issues but continues to be monitored. Note: drinking-water compliance speaks to the public water system, not necessarily to the watershed itself — check the Watershed Health zone for ATTAINS §303(d) data.
How does Jerome County rank for water quality in Idaho?
Jerome County ranks #13 out of 44 counties in Idaho by SDWIS water quality score (1 = best). With a score of 47.6/100, it falls in the top 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

Minidoka County

Idaho

D

48.4

Water score

Bear Lake County

Idaho

D

48.5

Water score

Bonneville County

Idaho

D

44.7

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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