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Federal water data

County water report

Glenn County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Glenn County, California.

Water grade

C

Water score

61.7

State rank

#12

of 58

Health violations

1

EPA SDWIS, 5-year lookback

Watershed impaired

43.5%

23 water bodies assessed

Monitoring sites

6

1,205 recent measurements

Live streamflow

No gauge

Primary USGS station not mapped

Water at a glance

Key Water Indicators for Glenn County

EPA SDWIS

Safety Grade

C

Score: 61.7 / 100

EPA SDWIS

Active Violations

1

5-year health-based lookback

EPA ATTAINS

Watershed Health

44% impaired

23 bodies assessed

USGS NWIS

Streamflow Snapshot

No gauge

Primary USGS gauge not mapped

EPA WQP

Monitoring Sites

6

1,205 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.

61.7/100

Health violations

1

Health-based violations

Violations per 100K served

5.3

Population-normalized SDWIS rate

Editorial analysis

Understanding Glenn County’s Water

Drinking Water Quality Overview

EPA SDWIS

Glenn County's drinking water earned a C grade, scoring 61.7 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). A substantial 43.5% of assessed waterways are impaired (10 of 23 water bodies) across Glenn County's watersheds. The leading impairment causes are mercury and toxicity. 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. Glenn County has limited coverage with 6 active monitoring sites with 1,205 recent measurements on record. Predominant monitoring categories include organics, pesticide and organics, other. 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 Glenn County

Water Verdict

Glenn County receives a fair water quality assessment with a grade of C and a score of 61.7 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring.

Violation Context

Glenn County has recorded 1 health-based violation, meaning the water system experienced at least one exceedance of federal contaminant limits or treatment requirements. At 5.3 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Glenn County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Glenn County's drinking-water compliance score is 61.7 out of 100. The violation rate for Glenn County is 5.3 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. Mercury is the leading impairment cause in Glenn County's watershed. There are 6 active water-quality monitoring sites in Glenn County.

Regional Context

Glenn County has better water quality than the average county in California. Its water score is 17.1 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 Glenn County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Mercury

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

  • 2

    Toxicity

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

  • 3

    Low dissolved oxygen

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Glenn County

EPA How's My Waterway

Interactive watershed health data for Glenn County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Glenn County

Consumer Confidence Reports (CA)

Annual water quality reports from utilities in California

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

43.5%

10 of 23 assessed

Moderate concern

Top Impairment Causes

  • 1

    MERCURY

  • 2

    TOXICITY

  • 3

    DISSOLVED OXYGEN

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

6

Active in the past 5 years

Measurements Recorded

1.2K

1,205 total readings

Most Measured

  • Organics, Pesticide
  • Organics, Other
  • PFAS,Perfluorinated Alkyl Substance

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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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 Glenn 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 Glenn County, California?
Glenn County, California has a drinking-water quality grade of C with a score of 61.7/100, 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 Glenn County?
Glenn 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 Glenn County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 43.5% of Glenn County's 23 assessed water bodies are classified as impaired (10 impaired). The top reported causes are MERCURY, TOXICITY, DISSOLVED OXYGEN. 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 Glenn County?
EPA's Water Quality Portal records 1,205 measurements from 6 monitoring sites in Glenn County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Organics, Other, PFAS,Perfluorinated Alkyl Substance. 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 Glenn County water compare to the California average?
Glenn County's SDWIS water quality score of 61.7/100 is higher than the California state average of 44.6. The average water quality grade across California is D, based on data from 58 counties with available SDWIS data.
Is tap water safe to drink in Glenn County?
Based on EPA SDWIS data, Glenn County has a water quality grade of C (61.7/100). 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).
Does Glenn County have clean drinking water?
Glenn County has 1 health-based drinking water violation according to EPA records. With a water quality score of 61.7/100 and grade C, 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 Glenn County rank for water quality in California?
Glenn County ranks #12 out of 58 counties in California by SDWIS water quality score (1 = best). With a score of 61.7/100, 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

Ventura County

California

B

63.0

Water score

Yuba County

California

C

59.8

Water score

Santa Barbara County

California

C

58.9

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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