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County water report

Monroe County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Monroe County, Illinois.

Water grade

C

Water score

58.7

State rank

#34

of 102

Health violations

2

EPA SDWIS, 5-year lookback

Watershed impaired

35.5%

217 water bodies assessed

Monitoring sites

7

393 recent measurements

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Monroe County

EPA SDWIS

Safety Grade

C

Score: 58.7 / 100

EPA SDWIS

Active Violations

2

5-year health-based lookback

EPA ATTAINS

Watershed Health

36% impaired

217 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

7

393 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

C

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

58.7/100

Health violations

2

Health-based violations

Violations per 100K served

7.4

Population-normalized SDWIS rate

Editorial analysis

Understanding Monroe County’s Water

Drinking Water Quality Overview

EPA SDWIS

Monroe County's drinking water earned a C grade, scoring 58.7 out of 100. Over the past five years, EPA SDWIS records 2 health-based violations — a small cluster that warrants attention.

Watershed Conditions

EPA ATTAINS

Under the Clean Water Act §303(d), EPA ATTAINS tracks whether waterways meet quality standards for drinking, recreation, and aquatic life (reporting cycle: 2022). A substantial 35.5% of assessed waterways are impaired (77 of 217 water bodies) across Monroe County's watersheds. The leading impairment causes are phosphorus, total and dissolved oxygen. Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Monroe County has limited coverage with 7 active monitoring sites with 393 recent measurements on record. Predominant monitoring categories include inorganics, minor, metals and physical. 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 Monroe County

Water Verdict

Monroe County receives a fair water quality assessment with a grade of C and a score of 58.7 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

Monroe County has recorded 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 7.4 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Monroe County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Monroe County's drinking-water compliance score is 58.7 out of 100. The violation rate for Monroe County is 7.4 per 100,000 people served. Residents who are immunocompromised, pregnant, or have young children may benefit from using an NSF 53-certified filter. Contacting your local utility for the current Consumer Confidence Report will confirm which specific violations were recorded and whether they have been resolved. Phosphorus, Total is the leading impairment cause in Monroe County's watershed. There are 7 active water-quality monitoring sites in Monroe County.

Regional Context

Monroe County has better water quality than the average county in Illinois. Its water score is 10.9 points higher than the state average, indicating stronger water system performance relative to 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 Monroe County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Phosphorus (excess nutrients)

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 2

    Low dissolved oxygen

    Impairment cause per EPA Clean Water Act §303(d) assessment

  • 3

    Alteration in Stream-Side Or Littoral Vegetative Covers

    Impairment cause per EPA Clean Water Act §303(d) assessment

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Monroe County

EPA How's My Waterway

Interactive watershed health data for Monroe County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Monroe County

Consumer Confidence Reports (IL)

Annual water quality reports from utilities in Illinois

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

35.5%

77 of 217 assessed

Moderate concern

Top Impairment Causes

  • 1

    PHOSPHORUS, TOTAL

  • 2

    DISSOLVED OXYGEN

  • 3

    ALTERATION IN STREAM-SIDE OR LITTORAL VEGETATIVE COVERS

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

7

Active in the past 5 years

Measurements Recorded

393

393 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).

Free tool

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Water Cost Estimate

3

3 people  ·  ~225 gal/day

Annual Total

$558

Monthly

$47

Water Bill

$558/yr

Filter Cost

$0/yr

Safety Grade for Monroe County:C — Moderate

Some violations or watershed impairment detected.

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 Monroe County, Illinois?
Monroe County, Illinois has a drinking-water quality grade of C with a score of 58.7/100, 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 streamflow snapshots are reported separately on this page.
Are there any water violations in Monroe County?
Monroe 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 Monroe County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 35.5% of Monroe County's 217 assessed water bodies are classified as impaired (77 impaired). The top reported causes are PHOSPHORUS, TOTAL, DISSOLVED OXYGEN, ALTERATION IN STREAM-SIDE OR LITTORAL VEGETATIVE COVERS. 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 Monroe County?
EPA's Water Quality Portal records 393 measurements from 7 monitoring sites in Monroe 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.
How does Monroe County water compare to the Illinois average?
Monroe County's SDWIS water quality score of 58.7/100 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 Monroe County?
Based on EPA SDWIS data, Monroe County has a water quality grade of C (58.7/100). 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 Monroe County have clean drinking water?
Monroe County has 2 health-based drinking water violations according to EPA records. With a water quality score of 58.7/100 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 Monroe County rank for water quality in Illinois?
Monroe County ranks #34 out of 102 counties in Illinois by SDWIS water quality score (1 = best). With a score of 58.7/100, it falls in the top 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

White County

Illinois

C

59.0

Water score

Lawrence County

Illinois

C

58.3

Water score

Montgomery County

Illinois

C

58.3

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 and 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.

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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