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County water report

Greene County Water Report

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

Water grade

A

Water score

70.8

State rank

#16

of 88

Health violations

1

EPA SDWIS, 5-year lookback

Watershed impaired

0.0%

9 water bodies assessed

Monitoring sites

29

3,953 recent measurements

Live streamflow

74%

Mad River near Dayton OH

Water at a glance

Key Water Indicators for Greene County

EPA SDWIS

Safety Grade

A

Score: 70.8 / 100

EPA SDWIS

Active Violations

1

5-year health-based lookback

EPA ATTAINS

Watershed Health

0% impaired

9 bodies assessed

USGS NWIS

Streamflow Snapshot

74% of mean

Mad River near Dayton OH

EPA WQP

Monitoring Sites

29

3,953 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

A

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

70.8/100

Health violations

1

Health-based violations

Violations per 100K served

0.6

Population-normalized SDWIS rate

Editorial analysis

Understanding Greene County’s Water

Drinking Water Quality Overview

EPA SDWIS

Greene County earns an A grade for drinking water quality, scoring 70.8 out of 100. Over the past five years, EPA SDWIS records 1 health-based violation — a single incident worth monitoring.

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 9 water bodies) across Greene 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 Mad River at 558.0 cfs — running somewhat below its historical average at 74% 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. Greene County has moderate coverage with 29 active monitoring sites with 3,953 recent measurements on record. Predominant monitoring categories include organics, pesticide 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 Greene County

Water Verdict

Greene County, Ohio receives a good water quality assessment with a grade of A and a score of 70.8 out of 100. While the water supply is generally safe, occasional monitoring gaps or minor contaminant detections may occur. Separately, EPA ATTAINS assessments track 9 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 73.9% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Greene County, Ohio show 1 health-based violation, meaning a water system experienced at least one exceedance of federal contaminant limits or treatment requirements. At 0.6 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. For independent context, 3,953 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Tap water in Greene County earns a Grade A overall with a small number of isolated health violations in the recent record. Greene County's drinking-water compliance score is 70.8 out of 100. The violation rate for Greene County is 0.6 per 100,000 people served. These violations were likely resolved quickly; Grade A reflects a strong multi-year compliance trend. Reviewing the most recent Consumer Confidence Report will show exactly which systems were affected and what corrective action was taken. With 29 active water-quality monitoring sites in Greene County, data coverage is strong. A pipeline streamflow snapshot from the Mad River gauge is also available on this page.

Regional Context

Greene County has better water quality than the average county in Ohio. Its water score is 14.6 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 Greene County's water environment

Official EPA Resources for Greene County

EPA How's My Waterway

Interactive watershed health data for Greene County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Greene 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 9 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

29

Active in the past 5 years

Measurements Recorded

4.0K

3,953 total readings

Most Measured

  • Organics, Pesticide
  • Physical
  • Organics, Other

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

558cfs

May 14, 6:30 PM UTC

vs Long-Term Average

74%

Below typical

Primary Streamgage

Mad River near Dayton OH

USGS site
03270000
Drainage area
635 sq mi
Long-term mean
755 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

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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 Greene 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 Greene County, Ohio?
Greene County, Ohio has a drinking-water quality grade of A with a score of 70.8/100, based on EPA SDWIS compliance data. The county has 1 health-based drinking water violation over the past 5 years. Watershed health, monitoring records, and streamflow snapshots are reported separately on this page.
Are there any water violations in Greene County?
Greene County has 1 health-based drinking water violation 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 Greene County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 0.0% of Greene County's 9 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 Greene County?
EPA's Water Quality Portal records 3,953 measurements from 29 monitoring sites in Greene County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Physical, Organics, Other. 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 Greene County right now?
Greene County's primary USGS streamgage on the Mad River has a pipeline snapshot of 558 cubic feet per second — 74% of the long-term mean of 754.62 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Greene County water compare to the Ohio average?
Greene County's SDWIS water quality score of 70.8/100 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 Greene County?
Based on EPA SDWIS data, Greene County has a water quality grade of A (70.8/100). 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 Greene County have clean drinking water?
Greene County has 1 health-based drinking water violation according to EPA records. With a water quality score of 70.8/100 and grade A, 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 Greene County rank for water quality in Ohio?
Greene County ranks #16 out of 88 counties in Ohio by SDWIS water quality score (1 = best). With a score of 70.8/100, 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

Mahoning County

Ohio

A

71.1

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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