waterbycounty
EPA SDWIS

Linn County Water Quality

Linn County, Iowa

Water Grade

B

Water Score

69.0

Violations

3

State Rank

#71

of 99 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

B

Based on EPA compliance history and violation data

Water Score

69/100

Higher = better quality

Health Violations

3

Health-based violations

Violation Rate

1.4%

Systems with violations

Water Advisory: Linn County

Water Verdict

Linn County receives a fair water quality assessment with a grade of B and a score of 69.0 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

Linn County has recorded 3 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 1.4 violations per 1,000 residents, this rate is relatively low compared to many U.S. counties.

Consumer Guidance

Tap water in Linn 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 3 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

Linn County has water quality close to the average county in Iowa. Its water score is within 2.7 points of the state average, meaning its overall water system performance is broadly representative of Iowa as a whole.

Past 5 years

Water Quality Monitoring

Monitoring Sites

27

Active in the past 5 years

Measurements Recorded

32K

32,404 total readings

Most Measured

  • Organics, Pesticide
  • Physical
  • 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

4,160cfs

May 14, 6:30 PM UTC

vs Long-Term Average

62%

Below typical

Primary Streamgage

Cedar River below Indian Creek at Cedar Rapids, IA

USGS site
05464730
Drainage area
6,830 sq mi
Long-term mean
6,736 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 Linn County, Iowa?
Linn County, Iowa has a drinking-water quality grade of B with a score of 69.0/100, based on EPA SDWIS compliance data. The county has 3 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 Linn County?
Linn County has 3 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 Linn County?
EPA's Water Quality Portal records 32,404 measurements from 27 monitoring sites in Linn County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Physical, 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 Linn County right now?
Linn County's primary USGS streamgage on the Cedar River below Indian Creek is currently reading 4,160 cubic feet per second — 62% of the long-term mean of 6,736 cfs. Flow is within typical range for this gauge. For genuine real-time data, visit waterdata.usgs.gov.
How does Linn County water compare to the Iowa average?
Linn County's SDWIS water quality score of 69.0/100 is lower than the Iowa state average of 71.7. The average water quality grade across Iowa is C, based on data from 99 counties with available SDWIS data.
Is tap water safe to drink in Linn County?
Based on EPA SDWIS data, Linn County has a water quality grade of B (69.0/100). 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 Linn County have clean drinking water?
Linn County has 3 health-based drinking water violations according to EPA records. With a water quality score of 69.0/100 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 Linn County rank for water quality in Iowa?
Linn County ranks #71 out of 99 counties in Iowa by SDWIS water quality score (1 = best). With a score of 69.0/100, 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

Polk County

Iowa

A

69.8

Water score

Scott County

Iowa

B

68.2

Water score

Woodbury County

Iowa

B

67.8

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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