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Federal water data

County water report

Ogle County Water Report

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

Water grade

C

Water score

60.8

State rank

#31

of 102

Health violations

2

EPA SDWIS, 5-year lookback

Watershed impaired

33.7%

282 water bodies assessed

Monitoring sites

3

924 recent measurements

Live streamflow

120%

ROCK RIVER AT BYRON, IL

Water at a glance

Key Water Indicators for Ogle County

EPA SDWIS

Safety Grade

C

Score: 60.8 / 100

EPA SDWIS

Active Violations

2

5-year health-based lookback

EPA ATTAINS

Watershed Health

34% impaired

282 bodies assessed

USGS NWIS

Streamflow Snapshot

120% of mean

ROCK RIVER AT BYRON, IL

EPA WQP

Monitoring Sites

3

924 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.

60.8/100

Health violations

2

Health-based violations

Violations per 100K served

5.9

Population-normalized SDWIS rate

Data center water stress

Ogle County has 2 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #144 nationally by combining its water score with mapped data center density.

DCWSIThe Data Center Water Stress Index: 60% the county's water-system stress plus 40% how concentrated data centers already are, scored 0-100. Higher means data-center density and water pressure overlap more here.

54.5

0-100 index

Facility count

2

45.0 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+10.8

Compared with US county median

Mapped facilities

  • ALLSTATE DATA CENTER

    ROCHELLE

    EPA ECHO

  • THE NORTHERN TRUST CO

    ROCHELLE

    EPA ECHO
See the Ogle County data-center reportReview methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Ogle County.

1 MW1,000 MW
40%100%
799K gallons/dayHigh Impact

Your facility would use 155.0% of this county's industrial water baseline. Verify water rights and long-term drought projections before committing.

155.0% of county industrial baseline

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding Ogle County’s Water

Drinking Water Quality Overview

EPA SDWIS

Ogle County's drinking water earned a C grade, scoring 60.8 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 33.7% of assessed waterways are impaired (95 of 282 water bodies) across Ogle County's watersheds. The leading impairment causes are mercury and polychlorinated biphenyls (pcbs). 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 ROCK RIVER at 9.0k cfs — flowing above its historical average at 120% 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. Ogle County has limited coverage with 3 active monitoring sites with 924 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 Ogle County

Water Verdict

Ogle County, Illinois receives a fair water quality assessment with a grade of C and a score of 60.8 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring. Separately, EPA ATTAINS assessments cover 282 water bodies in the county's watershed, with 33.7% 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 running above its historical mean at 119.9%.

Violation Context

EPA SDWIS records for Ogle County, Illinois show 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 5.9 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges. Independent monitoring is comparatively sparse here — 924 water-quality results logged in the EPA Water Quality Portal over the past five years — so the utility's own reporting carries extra weight.

Consumer Guidance

Tap water in Ogle County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Ogle County's drinking-water compliance score is 60.8 out of 100. The violation rate for Ogle County is 5.9 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. Mercury is the leading impairment cause in Ogle County's watershed. There are 3 active water-quality monitoring sites in Ogle County. A pipeline streamflow snapshot from the ROCK RIVER gauge is also available on this page.

Regional Context

Ogle County has better water quality than the average county in Illinois. Its water score is 13 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 Ogle County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Mercury

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

  • 2

    Polychlorinated Biphenyls (Pcbs)

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

  • 3

    Fecal coliform bacteria

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Ogle County

EPA How's My Waterway

Interactive watershed health data for Ogle County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Ogle County

Consumer Confidence Reports (IL)

Annual water quality reports from utilities in Illinois

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

33.7%

95 of 282 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

3

Active in the past 5 years

Measurements Recorded

924

924 total readings

Most Measured

  • Physical
  • Inorganics, Minor, Metals
  • 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

9,000cfs

May 14, 6:15 PM UTC

vs Long-Term Average

120%

Above typical

Primary Streamgage

ROCK RIVER AT BYRON, IL

USGS site
05440700
Drainage area
7,990 sq mi
Long-term mean
7,508 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 Ogle 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.

Try the full calculator →

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Frequently Asked Questions

What is the water quality in Ogle County, Illinois?
Ogle County, Illinois has a drinking-water quality grade of C with a score of 60.8/100, 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 Ogle County?
Ogle 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 Ogle County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 33.7% of Ogle County's 282 assessed water bodies are classified as impaired (95 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 Ogle County?
EPA's Water Quality Portal records 924 measurements from 3 monitoring sites in Ogle County over the past five years. The most frequently measured characteristic groups are Physical, Inorganics, Minor, Metals, 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 Ogle County right now?
Ogle County's primary USGS streamgage on the ROCK RIVER has a pipeline snapshot of 9,000 cubic feet per second — 120% of the long-term mean of 7,508.28 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Ogle County water compare to the Illinois average?
Ogle County's SDWIS water quality score of 60.8/100 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 Ogle County?
Based on EPA SDWIS data, Ogle County has a water quality grade of C (60.8/100). 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 Ogle County have clean drinking water?
Ogle County has 2 health-based drinking water violations according to EPA records. With a water quality score of 60.8/100 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 Ogle County rank for water quality in Illinois?
Ogle County ranks #31 out of 102 counties in Illinois by SDWIS water quality score (1 = best). With a score of 60.8/100, 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

St. Clair County

Illinois

C

61.0

Water score

Pike County

Illinois

C

60.4

Water score

White County

Illinois

C

59.0

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

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