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Federal water data

County water report

Caribou County Water Report

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

Water grade

F

Water score

36.7

State rank

#16

of 44

Health violations

2

EPA SDWIS, 5-year lookback

Watershed impaired

56.3%

636 water bodies assessed

Monitoring sites

171

10,554 recent measurements

Live streamflow

No gauge

BEAR RIVER BELOW GRACE DAM, NEAR GRACE, ID

Water at a glance

Key Water Indicators for Caribou County

EPA SDWIS

Safety Grade

F

Score: 36.7 / 100

EPA SDWIS

Active Violations

2

5-year health-based lookback

EPA ATTAINS

Watershed Health

56% impaired

636 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

BEAR RIVER BELOW GRACE DAM, NEAR GRACE, ID

EPA WQP

Monitoring Sites

171

10,554 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.

36.7/100

Health violations

2

Health-based violations

Violations per 100K served

41.5

Population-normalized SDWIS rate

Editorial analysis

Understanding Caribou County’s Water

Drinking Water Quality Overview

EPA SDWIS

Caribou County's water systems carry a failing grade, scoring 36.7 out of 100. Over the past five years, EPA SDWIS records 2 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 56.3% of assessed waterways are impaired (358 of 636 water bodies) across Caribou County's watersheds. The leading impairment causes are sedimentation/siltation and phosphorus, total. 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. Caribou County has extensive coverage with 171 active monitoring sites with 10,554 recent measurements on record. Predominant monitoring categories include physical and biological, counts. 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 Caribou County

Water Verdict

Caribou County receives a poor water quality assessment with a grade of F and a score of 36.7 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

Caribou County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 41.5 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Drinking-water compliance in Caribou County is rated Grade F, reflecting significant health-based violations in the recent reporting period. Caribou County's drinking-water compliance score is 36.7 out of 100. The violation rate for Caribou County is 41.5 per 100,000 people served. 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. Sedimentation/Siltation is the leading impairment cause in Caribou County's watershed. With 171 active water-quality monitoring sites in Caribou County, data coverage is strong. A pipeline streamflow snapshot from the BEAR RIVER BELOW GRACE DAM, gauge is also available on this page.

Regional Context

Caribou County has water quality close to the average county in Idaho. Its water score is within 4.1 points of the state average, meaning its overall water system performance is broadly representative of Idaho 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 Caribou County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Sedimentation and siltation

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

  • 2

    Phosphorus (excess nutrients)

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

  • 3

    E. coli (bacteria)

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Caribou County

EPA How's My Waterway

Interactive watershed health data for Caribou County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Caribou County

Consumer Confidence Reports (ID)

Annual water quality reports from utilities in Idaho

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

56.3%

358 of 636 assessed

Moderate concern

Top Impairment Causes

  • 1

    SEDIMENTATION/SILTATION

  • 2

    PHOSPHORUS, TOTAL

  • 3

    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

171

Active in the past 5 years

Measurements Recorded

11K

10,554 total readings

Most Measured

  • Physical
  • Biological, Counts
  • Biological, Fish

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

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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 Caribou County:F — Failing

High violation count or severe watershed conditions.

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 Caribou County, Idaho?
Caribou County, Idaho has a drinking-water quality grade of F with a score of 36.7/100, based on EPA SDWIS compliance data. The county has 2 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 Caribou County?
Caribou County has 2 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 Caribou County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 56.3% of Caribou County's 636 assessed water bodies are classified as impaired (358 impaired). The top reported causes are SEDIMENTATION/SILTATION, PHOSPHORUS, TOTAL, 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 Caribou County?
EPA's Water Quality Portal records 10,554 measurements from 171 monitoring sites in Caribou County over the past five years. The most frequently measured characteristic groups are Physical, Biological, Counts, Biological, Fish. 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 Caribou County water compare to the Idaho average?
Caribou County's SDWIS water quality score of 36.7/100 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 Caribou County?
Based on EPA SDWIS data, Caribou County has a water quality grade of F (36.7/100). 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 Caribou County have clean drinking water?
Caribou County has 2 health-based drinking water violations according to EPA records. With a water quality score of 36.7/100 and grade F, 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 Caribou County rank for water quality in Idaho?
Caribou County ranks #16 out of 44 counties in Idaho by SDWIS water quality score (1 = best). With a score of 36.7/100, 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

Lincoln County

Idaho

F

35.8

Water score

Teton County

Idaho

F

35.7

Water score

Kootenai County

Idaho

F

35.5

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

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