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County water report

Carter County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Carter County, Montana.

Water grade

A

Water score

86.0

State rank

#3

of 55

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

12 water bodies assessed

Monitoring sites

N/A

EPA Water Quality Portal

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Carter County

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

12 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

N/A

Rolling 5-year window

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

86.0/100

Health violations

0

Health-based violations

Violations per 100K served

0.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Carter County’s Water

Drinking Water Quality Overview

EPA SDWIS

Carter County earns an A grade for drinking water quality, scoring 86.0 out of 100. EPA's Safe Drinking Water Information System (SDWIS) records zero health-based violations over the past five years — a strong compliance signal for a small county.

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). None of the assessed waterways are listed as impaired (0 of 12 water bodies) across Carter County's watersheds. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Editorial advisory

What the data suggests for Carter County

Water Verdict

Carter County, Montana receives an excellent water quality assessment with a grade of A and a score of 86.0 out of 100. The water supply meets or exceeds federal safety standards, and residents can generally drink tap water with confidence. Separately, EPA ATTAINS assessments track 12 water bodies in the county's watershed, none of which are currently listed as impaired under the Clean Water Act.

Violation Context

EPA SDWIS records for Carter County, Montana show zero health-based violations, indicating that the county's water systems met all federal safety standards during the reporting period. The violation rate is zero per 100,000 people served, which is the best possible outcome. The most recent Clean Water Act assessment cycle on file for the county's watershed is 2022.

Consumer Guidance

The EPA compliance record for Carter County shows no recent health-based violations. No health-based violations have been recorded, placing Carter County in the top tier for drinking-water safety. Carter County's drinking-water compliance score is 86.0 out of 100. As a routine precaution, requesting your utility's annual Consumer Confidence Report each July gives you a full list of detected contaminants and their treatment levels.

Regional Context

Carter County has better water quality than the average county in Montana. Its water score is 37.1 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.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 12 assessed

Mostly healthy

Top Impairment Causes

No specific impairment causes reported for the assessed water bodies in this county.

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.

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3 people  ·  ~225 gal/day

Annual Total

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Monthly

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Filter Cost

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Safety Grade for Carter County:B — Good

Minor violations; waterways mostly healthy.

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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Carter County has good water quality

Learn about water restrictions and conservation in your area.

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Frequently Asked Questions

What is the water quality in Carter County, Montana?
Carter County, Montana has a drinking-water quality grade of A with a score of 86.0/100, based on EPA SDWIS compliance data. The county has 0 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 Carter County?
Carter County has 0 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). Zero violations is an excellent record indicating consistent compliance with federal drinking water standards.
How healthy are the watersheds in Carter County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Carter County's 12 assessed water bodies are classified as impaired (0 impaired). 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 does Carter County water compare to the Montana average?
Carter County's SDWIS water quality score of 86.0/100 is higher than the Montana state average of 48.9. The average water quality grade across Montana is D, based on data from 55 counties with available SDWIS data.
Is tap water safe to drink in Carter County?
Based on EPA SDWIS data, Carter County has a water quality grade of A (86.0/100). This indicates good to excellent water quality with strong SDWIS compliance. 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 Carter County have clean drinking water?
Carter County has 0 health-based drinking water violations according to EPA records. With a water quality score of 86.0/100 and grade A, the county's drinking water meets EPA standards with no recorded health violations. 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 Carter County rank for water quality in Montana?
Carter County ranks #3 out of 55 counties in Montana by SDWIS water quality score (1 = best). With a score of 86.0/100, 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

Big Horn County

Montana

A

86.0

Water score

Broadwater County

Montana

A

86.0

Water score

Daniels County

Montana

A

86.0

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.

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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