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EPA SDWIS

Cass County Water Quality

Cass County, North Dakota

Water Grade

B

Water Score

69.7

Violations

2

State Rank

#39

of 52 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

B

Based on EPA compliance history and violation data

Water Score

69.7/100

Higher = better quality

Health Violations

2

Health-based violations

Violation Rate

1.1%

Systems with violations

Water Advisory: Cass County

Water Verdict

Cass County receives a fair water quality assessment with a grade of B and a score of 69.7 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Cass County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 1.1 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Cass County is generally safe to drink based on available data. Residents should still review their utility's annual Consumer Confidence Report for transparency on detected contaminants. With 2 recorded health violations, staying informed about utility communications and boil-water notices is especially important. For long-term peace of mind, request your utility's latest Consumer Confidence Report and consider independent water testing if you have specific health concerns.

Regional Context

Cass County has water quality close to the average county in North Dakota. Its water score is within 1.9 points of the state average, meaning its overall water system performance is broadly representative of North Dakota as a whole.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

41.7%

25 of 60 assessed

Moderate concern

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

  • 2

    PHYSICAL SUBSTRATE HABITAT ALTERATIONS

  • 3

    COMBINED BIOTA/HABITAT BIOASSESSMENTS

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

29

Active in the past 5 years

Measurements Recorded

37K

37,474 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

403cfs

May 14, 7:00 PM UTC

vs Long-Term Average

121%

Above typical

Primary Streamgage

SHEYENNE RIVER AT WEST FARGO, ND

USGS site
05059500
Drainage area
8,870 sq mi
Long-term mean
334 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; "% of typical" compares the latest reading against that average.

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Frequently Asked Questions

What is the water quality in Cass County, North Dakota?
Cass County, North Dakota has a drinking-water quality grade of B with a score of 69.7/100, 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 live streamflow are reported separately on this page.
Are there any water violations in Cass County?
Cass 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 Cass County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 41.7% of Cass County's 60 assessed water bodies are classified as impaired (25 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI), PHYSICAL SUBSTRATE HABITAT ALTERATIONS, COMBINED BIOTA/HABITAT BIOASSESSMENTS. 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 Cass County?
EPA's Water Quality Portal records 37,474 measurements from 29 monitoring sites in Cass 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 Cass County right now?
Cass County's primary USGS streamgage on the SHEYENNE RIVER is currently reading 403 cubic feet per second — 121% of the long-term mean of 334.2 cfs. Flow is within typical range for this gauge. For genuine real-time data, visit waterdata.usgs.gov.
How does Cass County water compare to the North Dakota average?
Cass County's SDWIS water quality score of 69.7/100 is lower than the North Dakota state average of 71.6. The average water quality grade across North Dakota is C, based on data from 52 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 B (69.7/100). 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 Cass County have clean drinking water?
Cass County has 2 health-based drinking water violations according to EPA records. With a water quality score of 69.7/100 and grade B, 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 Cass County rank for water quality in North Dakota?
Cass County ranks #39 out of 52 counties in North Dakota by SDWIS water quality score (1 = best). With a score of 69.7/100, it falls in the bottom 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

Williams County

North Dakota

C

61.7

Water score

McKenzie County

North Dakota

C

57.5

Water score

Stutsman County

North Dakota

C

56.4

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, 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 Logan Johnson, Founder & Data EditorUpdated Reviewed by Logan Johnson, Founder & Data Editor

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