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County water report

Hamilton County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Hamilton County, Indiana.

Water grade

C

Water score

53.6

State rank

#45

of 92

Health violations

26

EPA SDWIS, 5-year lookback

Watershed impaired

72.2%

115 water bodies assessed

Monitoring sites

74

12,951 recent measurements

Live streamflow

63%

WHITE RIVER AT NOBLESVILLE, IN

Water at a glance

Key Water Indicators for Hamilton County

EPA SDWIS

Safety Grade

C

Score: 53.6 / 100

EPA SDWIS

Active Violations

26

5-year health-based lookback

EPA ATTAINS

Watershed Health

72% impaired

115 bodies assessed

USGS NWIS

Streamflow Snapshot

63% of mean

WHITE RIVER AT NOBLESVILLE, IN

EPA WQP

Monitoring Sites

74

12,951 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.

53.6/100

Health violations

26

Health-based violations

Violations per 100K served

11.8

Population-normalized SDWIS rate

Editorial analysis

Understanding Hamilton County’s Water

Drinking Water Quality Overview

EPA SDWIS

Hamilton County's drinking water earned a C grade, scoring 53.6 out of 100. Over the past five years, EPA SDWIS records 26 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 large majority — 72.2% — of assessed waterways are impaired (83 of 115 water bodies) across Hamilton County's watersheds. The leading impairment causes are escherichia coli (e. coli) and pcbs in fish tissue. 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 2026-05-14T14:45:00.000-04:00) puts WHITE RIVER at 586.0 cfs — running somewhat below its historical average at 63% 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. Hamilton County has extensive coverage with 74 active monitoring sites with 12,951 recent measurements on record. Predominant monitoring categories include physical and nutrient. 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 Hamilton County

Water Verdict

Hamilton County, Indiana receives a below-average water quality assessment with a grade of C and a score of 53.6 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 115 water bodies in the county's watershed, with 72.2% 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 62.9% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Hamilton County, Indiana show 26 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.8 violations per 100,000 people served, this rate is high and signals significant water quality management issues. This compliance record sits alongside an unusually deep monitoring archive: 12,951 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 Hamilton County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Hamilton County's drinking-water compliance score is 53.6 out of 100. The violation rate for Hamilton County is 11.8 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. E. coli is the leading impairment cause in Hamilton County's watershed. With 74 active water-quality monitoring sites in Hamilton County, data coverage is strong. A pipeline streamflow snapshot from the WHITE RIVER gauge is also available on this page.

Regional Context

Hamilton County has water quality close to the average county in Indiana. Its water score is within 1.1 points of the state average, meaning its overall water system performance is broadly representative of Indiana 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 Hamilton County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    E. coli (bacteria)

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

  • 2

    Pcbs in Fish Tissue

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

  • 3

    Biological Integrity

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Hamilton County

EPA How's My Waterway

Interactive watershed health data for Hamilton County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Hamilton County

Consumer Confidence Reports (IN)

Annual water quality reports from utilities in Indiana

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

72.2%

83 of 115 assessed

High concern

Top Impairment Causes

  • 1

    ESCHERICHIA COLI (E. COLI)

  • 2

    PCBS IN FISH TISSUE

  • 3

    BIOLOGICAL INTEGRITY

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

74

Active in the past 5 years

Measurements Recorded

13K

12,951 total readings

Most Measured

  • Physical
  • Nutrient
  • Inorganics, Minor, 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

586cfs

May 14, 6:45 PM UTC

vs Long-Term Average

63%

Below typical

Primary Streamgage

WHITE RIVER AT NOBLESVILLE, IN

USGS site
03349000
Drainage area
858 sq mi
Long-term mean
931 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.

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Water Cost Estimate

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Annual Total

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Monthly

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Water Bill

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Filter Cost

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Safety Grade for Hamilton 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.

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Frequently Asked Questions

What is the water quality in Hamilton County, Indiana?
Hamilton County, Indiana has a drinking-water quality grade of C with a score of 53.6/100, based on EPA SDWIS compliance data. The county has 26 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 Hamilton County?
Hamilton County has 26 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 Hamilton County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 72.2% of Hamilton County's 115 assessed water bodies are classified as impaired (83 impaired). The top reported causes are ESCHERICHIA COLI (E. COLI), PCBS IN FISH TISSUE, BIOLOGICAL INTEGRITY. 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 Hamilton County?
EPA's Water Quality Portal records 12,951 measurements from 74 monitoring sites in Hamilton County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Inorganics, Minor, 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 Hamilton County right now?
Hamilton County's primary USGS streamgage on the WHITE RIVER has a pipeline snapshot of 586 cubic feet per second — 63% of the long-term mean of 930.97 cfs. Flow is within typical range for this gauge. For the latest gauge feed, visit waterdata.usgs.gov.
How does Hamilton County water compare to the Indiana average?
Hamilton County's SDWIS water quality score of 53.6/100 is higher than the Indiana state average of 52.5. The average water quality grade across Indiana is D, based on data from 92 counties with available SDWIS data.
Is tap water safe to drink in Hamilton County?
Based on EPA SDWIS data, Hamilton County has a water quality grade of C (53.6/100). 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).
Why does Hamilton County have so many water violations?
Hamilton County has 26 health-based drinking water violations on record from the EPA SDWIS database. A higher violation count can result from aging infrastructure, underfunded water utilities, agricultural runoff contamination, or industrial pollution. Counties with more water systems may also see more violations simply due to scale. Residents concerned about water quality should consider independent water testing and home filtration systems.
How does Hamilton County rank for water quality in Indiana?
Hamilton County ranks #45 out of 92 counties in Indiana by SDWIS water quality score (1 = best). With a score of 53.6/100, 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

Clark County

Indiana

C

53.5

Water score

Perry County

Indiana

C

53.9

Water score

Fulton County

Indiana

C

53.2

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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