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EPA SDWIS

Whiteside County Water Quality

Whiteside County, Illinois

Water Grade

C

Water Score

52.3

Violations

5

State Rank

#46

of 102 (1 = best)

EPA SDWIS Compliance

Drinking Water Quality

Water Quality Grade

C

Based on EPA compliance history and violation data

Water Score

52.3/100

Higher = better quality

Health Violations

5

Health-based violations

Violation Rate

13.5%

Systems with violations

Water Advisory: Whiteside County

Water Verdict

Whiteside County receives a below-average water quality assessment with a grade of C and a score of 52.3 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking.

Violation Context

Whiteside County has recorded 5 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 13.5 violations per 1,000 residents, this rate is high and signals significant water quality management issues.

Consumer Guidance

Tap water in Whiteside 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 5 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

Whiteside County has water quality close to the average county in Illinois. Its water score is within 4.5 points of the state average, meaning its overall water system performance is broadly representative of Illinois as a whole.

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

30.4%

69 of 227 assessed

Moderate concern

Top Impairment Causes

  • 1

    MERCURY

  • 2

    POLYCHLORINATED BIPHENYLS (PCBS)

  • 3

    FECAL COLIFORM

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

12

Active in the past 5 years

Measurements Recorded

1.7K

1,651 total readings

Most Measured

  • Inorganics, Minor, Metals
  • Physical
  • Inorganics, Major, 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

9,390cfs

May 14, 7:00 PM UTC

vs Long-Term Average

145%

Well above typical

Primary Streamgage

ROCK RIVER AT COMO, IL

USGS site
05443500
Drainage area
8,753 sq mi
Long-term mean
6,486 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 Whiteside County, Illinois?
Whiteside County, Illinois has a drinking-water quality grade of C with a score of 52.3/100, based on EPA SDWIS compliance data. The county has 5 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 Whiteside County?
Whiteside County has 5 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 Whiteside County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 30.4% of Whiteside County's 227 assessed water bodies are classified as impaired (69 impaired). The top reported causes are MERCURY, POLYCHLORINATED BIPHENYLS (PCBS), FECAL COLIFORM. 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 Whiteside County?
EPA's Water Quality Portal records 1,651 measurements from 12 monitoring sites in Whiteside County over the past five years. The most frequently measured characteristic groups are Inorganics, Minor, Metals, Physical, Inorganics, Major, 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 Whiteside County right now?
Whiteside County's primary USGS streamgage on the ROCK RIVER is currently reading 9,390 cubic feet per second — 145% of the long-term mean of 6,485.8 cfs. This is well above typical — often a signal of recent precipitation or storm runoff. For genuine real-time data, visit waterdata.usgs.gov.
How does Whiteside County water compare to the Illinois average?
Whiteside County's SDWIS water quality score of 52.3/100 is higher than the Illinois state average of 47.8. The average water quality grade across Illinois is D, based on data from 102 counties with available SDWIS data.
Is tap water safe to drink in Whiteside County?
Based on EPA SDWIS data, Whiteside County has a water quality grade of C (52.3/100). 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 Whiteside County have clean drinking water?
Whiteside County has 5 health-based drinking water violations according to EPA records. With a water quality score of 52.3/100 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 Whiteside County rank for water quality in Illinois?
Whiteside County ranks #46 out of 102 counties in Illinois by SDWIS water quality score (1 = best). With a score of 52.3/100, 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

Hamilton County

Illinois

C

52.8

Water score

Rock Island County

Illinois

C

53.1

Water score

Knox County

Illinois

C

54.4

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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