waterbycounty
EPA SDWIS

Marion County Water Quality

Marion County, Missouri

Water Grade

C

Water Score

58.3

Violations

2

State Rank

#40

of 115 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

58.3/100

Higher = better quality

Health Violations

2

Health-based violations

Violation Rate

7.8%

Systems with violations

Water Advisory: Marion County

Water Verdict

Marion County receives a fair water quality assessment with a grade of C and a score of 58.3 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

Marion County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 7.8 violations per 1,000 residents, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Marion County meets baseline standards, but residents who are immunocompromised or have young children may want to use an NSF-certified water filter as a precaution. 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

Marion County has better water quality than the average county in Missouri. Its water score is 9.5 points higher than the state average, indicating stronger water system performance relative to neighboring counties.

Past 5 years

Water Quality Monitoring

Monitoring Sites

4

Active in the past 5 years

Measurements Recorded

1.9K

1,898 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Minor, Metals

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

48.5cfs

May 14, 6:30 PM UTC

vs Long-Term Average

11%

Well below typical

Primary Streamgage

South Fabius River near Taylor, MO

USGS site
05500000
Drainage area
620 sq mi
Long-term mean
435 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 Marion County, Missouri?
Marion County, Missouri has a drinking-water quality grade of C with a score of 58.3/100, 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 Marion County?
Marion 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 much water-quality monitoring happens in Marion County?
EPA's Water Quality Portal records 1,898 measurements from 4 monitoring sites in Marion County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Minor, Metals. 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 Marion County right now?
Marion County's primary USGS streamgage on the South Fabius River is currently reading 48.5 cubic feet per second — 11% of the long-term mean of 435.15 cfs. This is well below typical — often a signal of drought stress on source water. For genuine real-time data, visit waterdata.usgs.gov.
How does Marion County water compare to the Missouri average?
Marion County's SDWIS water quality score of 58.3/100 is higher 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 Marion County?
Based on EPA SDWIS data, Marion County has a water quality grade of C (58.3/100). 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).
Does Marion County have clean drinking water?
Marion County has 2 health-based drinking water violations according to EPA records. With a water quality score of 58.3/100 and grade C, 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 Marion County rank for water quality in Missouri?
Marion County ranks #40 out of 115 counties in Missouri by SDWIS water quality score (1 = best). With a score of 58.3/100, 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

Pulaski County

Missouri

C

58.3

Water score

Polk County

Missouri

C

59.6

Water score

Ray County

Missouri

C

59.8

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

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