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County water report

Johnson County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Johnson County, Tennessee.

Water grade

A

Water score

86.0

State rank

#32

of 95

Health violations

0

EPA SDWIS, 5-year lookback

Watershed impaired

24.7%

77 water bodies assessed

Monitoring sites

39

4,831 recent measurements

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Johnson County

EPA SDWIS

Safety Grade

A

Score: 86.0 / 100

EPA SDWIS

Active Violations

0

5-year health-based lookback

EPA ATTAINS

Watershed Health

25% impaired

77 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

39

4,831 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.

86.0/100

Health violations

0

Health-based violations

Violations per 100K served

0.0

Population-normalized SDWIS rate

Editorial analysis

Understanding Johnson County’s Water

Drinking Water Quality Overview

EPA SDWIS

Johnson County earns an A grade for drinking water quality, scoring 86.0 out of 100. EPA's Safe Drinking Water Information System (SDWIS) records zero health-based violations over the past five years — a strong compliance signal for a mid-sized county.

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 notable 24.7% of assessed waterways carry an impairment designation (19 of 77 water bodies) across Johnson County's watersheds. The leading impairment causes are alteration in stream-side or littoral vegetative covers and escherichia coli (e. coli). Impairment does not mean tap water is unsafe — it measures ambient waterway conditions upstream of treatment, not finished drinking water.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Johnson County has moderate coverage with 39 active monitoring sites with 4,831 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 Johnson County

Water Verdict

Johnson County receives an excellent water quality assessment with a grade of A and a score of 86.0 out of 100. The water supply meets or exceeds federal safety standards, and residents can generally drink tap water with confidence.

Violation Context

Johnson County has recorded zero health-based violations, indicating no recent health-based violations in the reporting period. The violation rate is zero per 100,000 people served, which is the best possible outcome.

Consumer Guidance

The EPA compliance record for Johnson County shows no recent health-based violations. No health-based violations have been recorded, placing Johnson County in the top tier for drinking-water safety. Johnson County's drinking-water compliance score is 86.0 out of 100. As a routine precaution, requesting your utility's annual Consumer Confidence Report each July gives you a full list of detected contaminants and their treatment levels. With 39 active water-quality monitoring sites in Johnson County, data coverage is strong.

Regional Context

Johnson County has better water quality than the average county in Tennessee. Its water score is 14.7 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 Johnson County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Alteration in Stream-Side Or Littoral Vegetative Covers

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

  • 2

    E. coli (bacteria)

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

  • 3

    Sedimentation and siltation

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Johnson County

EPA How's My Waterway

Interactive watershed health data for Johnson County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Johnson County

Consumer Confidence Reports (TN)

Annual water quality reports from utilities in Tennessee

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

24.7%

19 of 77 assessed

Some impairment

Top Impairment Causes

  • 1

    ALTERATION IN STREAM-SIDE OR LITTORAL VEGETATIVE COVERS

  • 2

    ESCHERICHIA COLI (E. COLI)

  • 3

    SEDIMENTATION/SILTATION

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

39

Active in the past 5 years

Measurements Recorded

4.8K

4,831 total readings

Most Measured

  • Physical
  • Nutrient
  • Biological, Counts

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).

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 Johnson County:B — Good

Minor violations; waterways mostly healthy.

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 →

Johnson County has good water quality

Learn about water restrictions and conservation in your area.

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Frequently Asked Questions

What is the water quality in Johnson County, Tennessee?
Johnson County, Tennessee has a drinking-water quality grade of A with a score of 86.0/100, based on EPA SDWIS compliance data. The county has 0 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 Johnson County?
Johnson County has 0 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). Zero violations is an excellent record indicating consistent compliance with federal drinking water standards.
How healthy are the watersheds in Johnson County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 24.7% of Johnson County's 77 assessed water bodies are classified as impaired (19 impaired). The top reported causes are ALTERATION IN STREAM-SIDE OR LITTORAL VEGETATIVE COVERS, ESCHERICHIA COLI (E. COLI), SEDIMENTATION/SILTATION. 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 Johnson County?
EPA's Water Quality Portal records 4,831 measurements from 39 monitoring sites in Johnson County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Biological, Counts. 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.
How does Johnson County water compare to the Tennessee average?
Johnson County's SDWIS water quality score of 86.0/100 is higher than the Tennessee state average of 71.3. The average water quality grade across Tennessee is C, based on data from 95 counties with available SDWIS data.
Is tap water safe to drink in Johnson County?
Based on EPA SDWIS data, Johnson County has a water quality grade of A (86.0/100). 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 Johnson County have clean drinking water?
Johnson County has 0 health-based drinking water violations according to EPA records. With a water quality score of 86.0/100 and grade A, the county's drinking water meets EPA standards with no recorded health violations. 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 Johnson County rank for water quality in Tennessee?
Johnson County ranks #32 out of 95 counties in Tennessee by SDWIS water quality score (1 = best). With a score of 86.0/100, 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

Anderson County

Tennessee

A

86.0

Water score

Benton County

Tennessee

A

86.0

Water score

Bradley County

Tennessee

A

86.0

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.

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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