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Federal water data

County water report

Knox County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Knox County, Maine.

Water grade

F

Water score

20.8

State rank

#9

of 16

Health violations

31

EPA SDWIS, 5-year lookback

Watershed impaired

50.0%

2 water bodies assessed

Monitoring sites

5

1,083 recent measurements

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Knox County

EPA SDWIS

Safety Grade

F

Score: 20.8 / 100

EPA SDWIS

Active Violations

31

5-year health-based lookback

EPA ATTAINS

Watershed Health

50% impaired

2 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

5

1,083 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

F

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

20.8/100

Health violations

31

Health-based violations

Violations per 100K served

122.2

Population-normalized SDWIS rate

Editorial analysis

Understanding Knox County’s Water

Drinking Water Quality Overview

EPA SDWIS

Knox County's water systems carry a failing grade, scoring 20.8 out of 100. Over the past five years, EPA SDWIS records 31 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 substantial 50.0% of assessed waterways are impaired (1 of 2 water bodies) across Knox County's watersheds. The leading impairment causes are dioxin (including 2,3,7,8-tcdd) and polychlorinated biphenyls (pcbs). 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. Knox County has limited coverage with 5 active monitoring sites with 1,083 recent measurements on record. Predominant monitoring categories include physical and microbiological. 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 Knox County

Water Verdict

Knox County, Maine receives a poor water quality assessment with a grade of F and a score of 20.8 out of 100. The water supply has documented quality issues. Residents are strongly encouraged to use filtered or bottled water for drinking and to stay informed about utility improvement plans. Separately, EPA ATTAINS assessments cover 2 water bodies in the county's watershed, with 50.0% listed as impaired under the Clean Water Act — a source-water measure that is tracked independently of tap-water compliance.

Violation Context

EPA SDWIS records for Knox County, Maine show 31 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 122.2 violations per 100,000 people served, this rate is high and signals significant water quality management issues. For independent context, 1,083 water-quality monitoring results have been recorded across the county in the EPA Water Quality Portal over the past five years.

Consumer Guidance

Knox County has a Grade F compliance record with 31 health-based violations — among the highest levels in the country. Knox County's drinking-water compliance score is 20.8 out of 100. Residents are strongly advised to use a certified NSF 58 reverse-osmosis filter or bottled water for all drinking and cooking until violations are corrected. Contacting the Maine Department of Environmental Quality or Health can expedite utility compliance action. Dioxin (Including 2,3,7,8-Tcdd) is the leading impairment cause in Knox County's watershed. There are 5 active water-quality monitoring sites in Knox County.

Regional Context

Knox County has poorer water quality than the average county in Maine. Its water score is 9.3 points lower than the state average, suggesting more challenges with contamination control or infrastructure than 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 Knox County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Dioxin (Including 2,3,7,8-Tcdd)

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

  • 2

    Polychlorinated Biphenyls (Pcbs)

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Knox County

EPA How's My Waterway

Interactive watershed health data for Knox County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Knox County

Consumer Confidence Reports (ME)

Annual water quality reports from utilities in Maine

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

50.0%

1 of 2 assessed

Moderate concern

Top Impairment Causes

  • 1

    DIOXIN (INCLUDING 2,3,7,8-TCDD)

  • 2

    POLYCHLORINATED BIPHENYLS (PCBS)

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

5

Active in the past 5 years

Measurements Recorded

1.1K

1,083 total readings

Most Measured

  • Physical
  • Microbiological
  • Nutrient

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).

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Annual Total

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Monthly

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Filter Cost

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Safety Grade for Knox County:F — Failing

High violation count or severe watershed conditions.

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 Knox County, Maine?
Knox County, Maine has a drinking-water quality grade of F with a score of 20.8/100, based on EPA SDWIS compliance data. The county has 31 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 Knox County?
Knox County has 31 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 Knox County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 50.0% of Knox County's 2 assessed water bodies are classified as impaired (1 impaired). The top reported causes are DIOXIN (INCLUDING 2,3,7,8-TCDD), POLYCHLORINATED BIPHENYLS (PCBS). 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 Knox County?
EPA's Water Quality Portal records 1,083 measurements from 5 monitoring sites in Knox County over the past five years. The most frequently measured characteristic groups are Physical, Microbiological, Nutrient. 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 Knox County water compare to the Maine average?
Knox County's SDWIS water quality score of 20.8/100 is lower than the Maine state average of 30.1. The average water quality grade across Maine is F, based on data from 16 counties with available SDWIS data.
Is tap water safe to drink in Knox County?
Based on EPA SDWIS data, Knox County has a water quality grade of F (20.8/100). This indicates below-average compliance with significant violations. Residents may want to consider home water filtration or independent testing. 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 Knox County have so many water violations?
Knox County has 31 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 Knox County rank for water quality in Maine?
Knox County ranks #9 out of 16 counties in Maine by SDWIS water quality score (1 = best). With a score of 20.8/100, 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

Somerset County

Maine

F

16.7

Water score

Aroostook County

Maine

F

15.0

Water score

Franklin County

Maine

F

12.5

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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