waterbycounty
Federal water data

County water report

Jo Daviess County Water Report

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

Water grade

D

Water score

43.2

State rank

#53

of 102

Health violations

4

EPA SDWIS, 5-year lookback

Watershed impaired

53.4%

369 water bodies assessed

Monitoring sites

10

2,730 recent measurements

Live streamflow

77%

APPLE RIVER NEAR HANOVER, IL

Water at a glance

Key Water Indicators for Jo Daviess County

EPA SDWIS

Safety Grade

D

Score: 43.2 / 100

EPA SDWIS

Active Violations

4

5-year health-based lookback

EPA ATTAINS

Watershed Health

53% impaired

369 bodies assessed

USGS NWIS

Streamflow Snapshot

77% of mean

APPLE RIVER NEAR HANOVER, IL

EPA WQP

Monitoring Sites

10

2,730 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

D

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

43.2/100

Health violations

4

Health-based violations

Violations per 100K served

26.6

Population-normalized SDWIS rate

Editorial analysis

Understanding Jo Daviess County’s Water

Drinking Water Quality Overview

EPA SDWIS

Jo Daviess County's drinking water received a D grade, scoring 43.2 out of 100. Over the past five years, EPA SDWIS records 4 health-based violations — a pattern that public water utilities are required to disclose and correct.

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 53.4% of assessed waterways are impaired (197 of 369 water bodies) across Jo Daviess County's watersheds. The leading impairment causes are phosphorus, total and total suspended solids (tss). Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T12:15:00.000-06:00) puts APPLE RIVER at 152.0 cfs — running somewhat below its historical average at 77% of mean. Streamflow is a leading indicator of drought stress, sediment load, and dilution capacity: low flows concentrate pollutants and warm water temperatures, stressing aquatic life and, in surface-water-dependent systems, the source water quality for treatment plants.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Jo Daviess County has moderate coverage with 10 active monitoring sites with 2,730 recent measurements on record. Predominant monitoring categories include physical and inorganics, minor, metals. 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 Jo Daviess County

Water Verdict

Jo Daviess County, Illinois receives a below-average water quality assessment with a grade of D and a score of 43.2 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking. Separately, EPA ATTAINS assessments cover 369 water bodies in the county's watershed, with 53.4% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance. At the most recent USGS reading, local streamflow was below its historical mean at 77.0% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Jo Daviess County, Illinois show 4 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 26.6 violations per 100,000 people served, this rate is high and signals significant water quality management issues. For independent context, 2,730 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Jo Daviess County's drinking-water compliance is below average with a Grade D, indicating repeated or unresolved violations in the recent record. Jo Daviess County's drinking-water compliance score is 43.2 out of 100. The violation rate for Jo Daviess County is 26.6 per 100,000 people served. Residents are encouraged to use an NSF 53 or NSF 58-certified filter for drinking and cooking water until the underlying violations are resolved. Running tap water for 30 seconds before use and avoiding older lead-pipe connections can also reduce exposure risk. The current Consumer Confidence Report from your utility will specify the contaminants of concern. Phosphorus, Total is the leading impairment cause in Jo Daviess County's watershed. There are 10 active water-quality monitoring sites in Jo Daviess County. A pipeline streamflow snapshot from the APPLE RIVER gauge is also available on this page.

Regional Context

Jo Daviess County has water quality close to the average county in Illinois. Its water score is within 4.6 points of the state average, meaning its overall water system performance is broadly representative of Illinois as a whole.

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 Jo Daviess County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Phosphorus (excess nutrients)

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

  • 2

    Total Suspended Solids (Tss)

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

  • 3

    Cause Unknown

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Jo Daviess County

EPA How's My Waterway

Interactive watershed health data for Jo Daviess County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Jo Daviess County

Consumer Confidence Reports (IL)

Annual water quality reports from utilities in Illinois

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

53.4%

197 of 369 assessed

Moderate concern

Top Impairment Causes

  • 1

    PHOSPHORUS, TOTAL

  • 2

    TOTAL SUSPENDED SOLIDS (TSS)

  • 3

    CAUSE UNKNOWN

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

10

Active in the past 5 years

Measurements Recorded

2.7K

2,730 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

152cfs

May 14, 6:15 PM UTC

vs Long-Term Average

77%

Below typical

Primary Streamgage

APPLE RIVER NEAR HANOVER, IL

USGS site
05419000
Drainage area
246 sq mi
Long-term mean
197 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; the percent-of-typical value compares the latest reading against that average.

Free tool

Estimate Your Water Costs

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 Jo Daviess County:D — Poor

Elevated violations or significant watershed impairment.

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.

Try the full calculator →

Improve your water quality at home

Berkey filters remove 99.9%+ of contaminants from tap water.

Shop Berkey →

Sponsored

Test your tap water

Tap Score provides professional mail-in water testing.

Get Tested →

Frequently Asked Questions

What is the water quality in Jo Daviess County, Illinois?
Jo Daviess County, Illinois has a drinking-water quality grade of D with a score of 43.2/100, based on EPA SDWIS compliance data. The county has 4 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 Jo Daviess County?
Jo Daviess County has 4 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 Jo Daviess County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 53.4% of Jo Daviess County's 369 assessed water bodies are classified as impaired (197 impaired). The top reported causes are PHOSPHORUS, TOTAL, TOTAL SUSPENDED SOLIDS (TSS), CAUSE UNKNOWN. 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 Jo Daviess County?
EPA's Water Quality Portal records 2,730 measurements from 10 monitoring sites in Jo Daviess 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 Jo Daviess County right now?
Jo Daviess County's primary USGS streamgage on the APPLE RIVER has a pipeline snapshot of 152 cubic feet per second — 77% of the long-term mean of 197.33 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Jo Daviess County water compare to the Illinois average?
Jo Daviess County's SDWIS water quality score of 43.2/100 is lower 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 Jo Daviess County?
Based on EPA SDWIS data, Jo Daviess County has a water quality grade of D (43.2/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. 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 Jo Daviess County have clean drinking water?
Jo Daviess County has 4 health-based drinking water violations according to EPA records. With a water quality score of 43.2/100 and grade D, 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 Jo Daviess County rank for water quality in Illinois?
Jo Daviess County ranks #53 out of 102 counties in Illinois by SDWIS water quality score (1 = best). With a score of 43.2/100, 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

Macon County

Illinois

D

42.8

Water score

Mason County

Illinois

D

44.4

Water score

Massac County

Illinois

D

41.8

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.

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.

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 Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

Explore more data for Jo Daviess County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsDisaster RiskWeatherCounty Score