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County water report

Clermont County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Clermont County, Ohio.

Water grade

B

Water score

69.7

State rank

#20

of 88

Health violations

2

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

2 water bodies assessed

Monitoring sites

10

11,071 recent measurements

Live streamflow

61%

Little Miami River at Milford OH

Water at a glance

Key Water Indicators for Clermont County

EPA SDWIS

Safety Grade

B

Score: 69.7 / 100

EPA SDWIS

Active Violations

2

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

2 bodies assessed

USGS NWIS

Streamflow Snapshot

61% of mean

Little Miami River at Milford OH

EPA WQP

Monitoring Sites

10

11,071 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

B

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

69.7/100

Health violations

2

Health-based violations

Violations per 100K served

1.1

Population-normalized SDWIS rate

Editorial analysis

Understanding Clermont County’s Water

Drinking Water Quality Overview

EPA SDWIS

Clermont County earns a B grade for drinking water quality, scoring 69.7 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). None of the assessed waterways are listed as impaired (0 of 2 water bodies) across Clermont County's watersheds. 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 2026-05-14T14:30:00.000-04:00) puts Little Miami River at 821.0 cfs — running somewhat below its historical average at 61% 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. Clermont County has moderate coverage with 10 active monitoring sites with 11,071 recent measurements on record. Predominant monitoring categories include nutrient 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 Clermont County

Water Verdict

Clermont County, Ohio receives a fair water quality assessment with a grade of B and a score of 69.7 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring. Separately, EPA ATTAINS assessments track 2 water bodies in the county's watershed, none of which are currently listed as impaired under the Clean Water Act. At the most recent USGS reading, local streamflow was below its historical mean at 61.3% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Clermont County, Ohio show 2 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 1.1 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. This compliance record sits alongside an unusually deep monitoring archive: 11,071 water-quality results have been logged across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Clermont County scores well above average for drinking-water safety. Clermont County's drinking-water compliance score is 69.7 out of 100. With 2 recorded health violations, the water supply is generally reliable. The violation rate for Clermont County is 1.1 per 100,000 people served. Households with infants, pregnant individuals, or immunocompromised members may want to use an NSF 53-certified pitcher filter as a low-cost precaution. There are 10 active water-quality monitoring sites in Clermont County. A pipeline streamflow snapshot from the Little Miami River gauge is also available on this page.

Regional Context

Clermont County has better water quality than the average county in Ohio. Its water score is 13.5 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 Clermont County's water environment

Official EPA Resources for Clermont County

EPA How's My Waterway

Interactive watershed health data for Clermont County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Clermont County

Consumer Confidence Reports (OH)

Annual water quality reports from utilities in Ohio

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

0.0%

0 of 2 assessed

Mostly healthy

Top Impairment Causes

No specific impairment causes reported for the assessed water bodies in this county.

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

11K

11,071 total readings

Most Measured

  • Nutrient
  • Physical
  • Sediment

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

821cfs

May 14, 6:30 PM UTC

vs Long-Term Average

61%

Below typical

Primary Streamgage

Little Miami River at Milford OH

USGS site
03245500
Drainage area
1,203 sq mi
Long-term mean
1,340 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 Clermont 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 Clermont County, Ohio?
Clermont County, Ohio has a drinking-water quality grade of B with a score of 69.7/100, 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 Clermont County?
Clermont 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 Clermont County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Clermont County's 2 assessed water bodies are classified as impaired (0 impaired). 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 Clermont County?
EPA's Water Quality Portal records 11,071 measurements from 10 monitoring sites in Clermont County over the past five years. The most frequently measured characteristic groups are Nutrient, Physical, Sediment. 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 Clermont County right now?
Clermont County's primary USGS streamgage on the Little Miami River has a pipeline snapshot of 821 cubic feet per second — 61% of the long-term mean of 1,339.59 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Clermont County water compare to the Ohio average?
Clermont County's SDWIS water quality score of 69.7/100 is higher than the Ohio state average of 56.2. The average water quality grade across Ohio is D, based on data from 88 counties with available SDWIS data.
Is tap water safe to drink in Clermont County?
Based on EPA SDWIS data, Clermont County has a water quality grade of B (69.7/100). 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 Clermont County have clean drinking water?
Clermont County has 2 health-based drinking water violations according to EPA records. With a water quality score of 69.7/100 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 Clermont County rank for water quality in Ohio?
Clermont County ranks #20 out of 88 counties in Ohio by SDWIS water quality score (1 = best). With a score of 69.7/100, 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

Montgomery County

Ohio

A

69.8

Water score

Lake County

Ohio

A

70.1

Water score

Lucas County

Ohio

A

70.1

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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