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Federal water data

County water report

Cass County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Cass County, Missouri.

Water grade

F

Water score

37.1

State rank

#71

of 115

Health violations

45

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

14

2,524 recent measurements

Live streamflow

19%

South Grand River at Archie, MO

Water at a glance

Key Water Indicators for Cass County

EPA SDWIS

Safety Grade

F

Score: 37.1 / 100

EPA SDWIS

Active Violations

45

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

19% of mean

South Grand River at Archie, MO

EPA WQP

Monitoring Sites

14

2,524 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.

37.1/100

Health violations

45

Health-based violations

Violations per 100K served

40.2

Population-normalized SDWIS rate

Editorial analysis

Understanding Cass County’s Water

Drinking Water Quality Overview

EPA SDWIS

Cass County's water systems carry a failing grade, scoring 37.1 out of 100. Over the past five years, EPA SDWIS records 45 health-based violations — a pattern that public water utilities are required to disclose and correct.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T13:30:00.000-05:00) puts South Grand River at 52.8 cfs — well below its long-term average at 19% of mean — low-flow conditions worth noting for water-dependent ecosystems. 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. Cass County has moderate coverage with 14 active monitoring sites with 2,524 recent measurements on record. Predominant monitoring categories include physical and nutrient. 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 Cass County

Water Verdict

Cass County receives a poor water quality assessment with a grade of F and a score of 37.1 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

Cass County has recorded 45 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 40.2 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Cass County has a Grade F compliance record with 45 health-based violations — among the highest levels in the country. Cass County's drinking-water compliance score is 37.1 out of 100. The violation rate for Cass County is 40.2 per 100,000 people served. Residents are strongly advised to use a certified NSF 58 reverse-osmosis filter or bottled water for all drinking and cooking until violations are corrected. Contacting the Missouri Department of Environmental Quality or Health can expedite utility compliance action. With 14 active water-quality monitoring sites in Cass County, data coverage is strong. A pipeline streamflow snapshot from the South Grand River gauge is also available on this page.

Regional Context

Cass County has poorer water quality than the average county in Missouri. Its water score is 11.7 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 Cass County's water environment

Official EPA Resources for Cass County

EPA How's My Waterway

Interactive watershed health data for Cass County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Cass County

Consumer Confidence Reports (MO)

Annual water quality reports from utilities in Missouri

Past 5 years

Water Quality Monitoring

Monitoring Sites

14

Active in the past 5 years

Measurements Recorded

2.5K

2,524 total readings

Most Measured

  • Physical
  • Nutrient
  • Cyanotoxins, Phytotoxins

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

52.8cfs

May 14, 6:30 PM UTC

vs Long-Term Average

19%

Well below typical

Primary Streamgage

South Grand River at Archie, MO

USGS site
06921590
Drainage area
356 sq mi
Long-term mean
285 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.

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Water Cost Estimate

3

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Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Cass 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 Cass County, Missouri?
Cass County, Missouri has a drinking-water quality grade of F with a score of 37.1/100, based on EPA SDWIS compliance data. The county has 45 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 Cass County?
Cass County has 45 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 much water-quality monitoring happens in Cass County?
EPA's Water Quality Portal records 2,524 measurements from 14 monitoring sites in Cass County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Cyanotoxins, Phytotoxins. 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 Cass County right now?
Cass County's primary USGS streamgage on the South Grand River has a pipeline snapshot of 52.8 cubic feet per second — 19% of the long-term mean of 285.45 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Cass County water compare to the Missouri average?
Cass County's SDWIS water quality score of 37.1/100 is lower than the Missouri state average of 48.8. The average water quality grade across Missouri is D, based on data from 115 counties with available SDWIS data.
Is tap water safe to drink in Cass County?
Based on EPA SDWIS data, Cass County has a water quality grade of F (37.1/100). 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 Cass County have so many water violations?
Cass County has 45 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 Cass County rank for water quality in Missouri?
Cass County ranks #71 out of 115 counties in Missouri by SDWIS water quality score (1 = best). With a score of 37.1/100, 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

Gasconade County

Missouri

F

36.9

Water score

Lewis County

Missouri

F

36.2

Water score

Dunklin County

Missouri

F

38.1

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.

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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