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Federal water data

County water report

Cascade County Water Report

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

Water grade

C

Water score

54.3

State rank

#25

of 55

Health violations

9

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

28 water bodies assessed

Monitoring sites

58

17,176 recent measurements

Live streamflow

77%

Missouri River near Great Falls MT

Water at a glance

Key Water Indicators for Cascade County

EPA SDWIS

Safety Grade

C

Score: 54.3 / 100

EPA SDWIS

Active Violations

9

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

28 bodies assessed

USGS NWIS

Streamflow Snapshot

77% of mean

Missouri River near Great Falls MT

EPA WQP

Monitoring Sites

58

17,176 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

C

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

54.3/100

Health violations

9

Health-based violations

Violations per 100K served

11.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Cascade County’s Water

Drinking Water Quality Overview

EPA SDWIS

Cascade County's drinking water earned a C grade, scoring 54.3 out of 100. Over the past five years, EPA SDWIS records 9 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). None of the assessed waterways are listed as impaired (0 of 28 water bodies) across Cascade County's watersheds. 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 2026-05-14T12:45:00.000-06:00) puts Missouri River at 5.5k cfs — running somewhat below its historical average at 77% 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. Cascade County has extensive coverage with 58 active monitoring sites with 17,176 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 Cascade County

Water Verdict

Cascade County, Montana receives a below-average water quality assessment with a grade of C and a score of 54.3 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 track 28 water bodies in the county's watershed, none of which are currently listed as impaired under the Clean Water Act. At the most recent USGS reading, local streamflow was below its historical mean at 76.9% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Cascade County, Montana show 9 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.0 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: 17,176 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Cascade County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Cascade County's drinking-water compliance score is 54.3 out of 100. The violation rate for Cascade County is 11.0 per 100,000 people served. Residents who are immunocompromised, pregnant, or have young children may benefit from using an NSF 53-certified filter. Contacting your local utility for the current Consumer Confidence Report will confirm which specific violations were recorded and whether they have been resolved. With 58 active water-quality monitoring sites in Cascade County, data coverage is strong. A pipeline streamflow snapshot from the Missouri River gauge is also available on this page.

Regional Context

Cascade County has better water quality than the average county in Montana. Its water score is 5.4 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 Cascade County's water environment

Official EPA Resources for Cascade County

EPA How's My Waterway

Interactive watershed health data for Cascade County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Cascade County

Consumer Confidence Reports (MT)

Annual water quality reports from utilities in Montana

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 28 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.

Past 5 years

Water Quality Monitoring

Monitoring Sites

58

Active in the past 5 years

Measurements Recorded

17K

17,176 total readings

Most Measured

  • Physical
  • Inorganics, Minor, Metals
  • 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

5,500cfs

May 14, 6:45 PM UTC

vs Long-Term Average

77%

Below typical

Primary Streamgage

Missouri River near Great Falls MT

USGS site
06090300
Drainage area
22,881 sq mi
Long-term mean
7,152 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

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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 Cascade 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 Cascade County, Montana?
Cascade County, Montana has a drinking-water quality grade of C with a score of 54.3/100, based on EPA SDWIS compliance data. The county has 9 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 Cascade County?
Cascade County has 9 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 Cascade County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Cascade County's 28 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 much water-quality monitoring happens in Cascade County?
EPA's Water Quality Portal records 17,176 measurements from 58 monitoring sites in Cascade County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, Metals, 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 Cascade County right now?
Cascade County's primary USGS streamgage on the Missouri River has a pipeline snapshot of 5,500 cubic feet per second — 77% of the long-term mean of 7,151.97 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Cascade County water compare to the Montana average?
Cascade County's SDWIS water quality score of 54.3/100 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 Cascade County?
Based on EPA SDWIS data, Cascade County has a water quality grade of C (54.3/100). This indicates moderate compliance. Some violations have been recorded but overall standards are maintained. 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 Cascade County have so many water violations?
Cascade County has 9 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 Cascade County rank for water quality in Montana?
Cascade County ranks #25 out of 55 counties in Montana by SDWIS water quality score (1 = best). With a score of 54.3/100, 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

Gallatin County

Montana

C

54.3

Water score

Flathead County

Montana

C

55.0

Water score

Ravalli County

Montana

C

56.9

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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