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County water report

Summit County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Summit County, Colorado.

Water grade

C

Water score

54.0

State rank

#19

of 64

Health violations

8

EPA SDWIS, 5-year lookback

Watershed impaired

38.7%

31 water bodies assessed

Monitoring sites

53

14,008 recent measurements

Live streamflow

14%

BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO

Water at a glance

Key Water Indicators for Summit County

EPA SDWIS

Safety Grade

C

Score: 54.0 / 100

EPA SDWIS

Active Violations

8

5-year health-based lookback

EPA ATTAINS

Watershed Health

39% impaired

31 bodies assessed

USGS NWIS

Streamflow Snapshot

14% of mean

BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO

EPA WQP

Monitoring Sites

53

14,008 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.

54.0/100

Health violations

8

Health-based violations

Violations per 100K served

11.2

Population-normalized SDWIS rate

Editorial analysis

Understanding Summit County’s Water

Drinking Water Quality Overview

EPA SDWIS

Summit County's drinking water earned a C grade, scoring 54.0 out of 100. Over the past five years, EPA SDWIS records 8 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 38.7% of assessed waterways are impaired (12 of 31 water bodies) across Summit County's watersheds. The leading impairment causes are arsenic and zinc. 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 2026-05-14T13:00:00.000-06:00) puts BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO at 62.5 cfs — well below its long-term average at 14% of mean — low-flow conditions worth noting for water-dependent ecosystems. 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. Summit County has extensive coverage with 53 active monitoring sites with 14,008 recent measurements on record. Predominant monitoring categories include nutrient 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 Summit County

Water Verdict

Summit County receives a below-average water quality assessment with a grade of C and a score of 54.0 out of 100. Residents should review their utility's Consumer Confidence Report and may want to consider additional water filtration for drinking.

Violation Context

Summit County has recorded 8 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.2 violations per 100,000 people served, this rate is high and signals significant water quality management issues.

Consumer Guidance

Residents of Summit County should be aware that arsenic has been identified as a watershed impairment cause, and drinking-water compliance is at a C-grade level. Summit County's drinking-water compliance score is 54.0 out of 100. Long-term low-level arsenic exposure is a health concern; an NSF 58-certified reverse-osmosis filter is the most effective point-of-use option for arsenic removal. Reviewing your utility's Consumer Confidence Report will show whether treated water meets the EPA's 10 ppb MCL. The violation rate for Summit County is 11.2 per 100,000 people served. With 53 active water-quality monitoring sites in Summit County, data coverage is strong. A pipeline streamflow snapshot from the BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO gauge is also available on this page.

Regional Context

Summit County has better water quality than the average county in Colorado. Its water score is 15.3 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 Summit County's water environment

Watershed Impairment Causes (EPA ATTAINS)

  • 1

    Arsenic

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

  • 2

    Zinc

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

  • 3

    Benthic Macroinvertebrates

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

Source: EPA ATTAINS · Reporting cycle 2022

Official EPA Resources for Summit County

EPA How's My Waterway

Interactive watershed health data for Summit County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Summit County

Consumer Confidence Reports (CO)

Annual water quality reports from utilities in Colorado

Clean Water Act §303(d)

Watershed Health

Impaired Water Bodies

38.7%

12 of 31 assessed

Moderate concern

Top Impairment Causes

  • 1

    ARSENIC

  • 2

    ZINC

  • 3

    BENTHIC MACROINVERTEBRATES

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

53

Active in the past 5 years

Measurements Recorded

14K

14,008 total readings

Most Measured

  • Nutrient
  • Physical
  • 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

62.5cfs

May 14, 7:00 PM UTC

vs Long-Term Average

14%

Well below typical

Primary Streamgage

BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO

USGS site
09057500
Drainage area
597 sq mi
Long-term mean
441 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

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 Summit 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 Summit County, Colorado?
Summit County, Colorado has a drinking-water quality grade of C with a score of 54.0/100, based on EPA SDWIS compliance data. The county has 8 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 Summit County?
Summit County has 8 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 Summit County?
EPA ATTAINS assessments under Clean Water Act §303(d) indicate 38.7% of Summit County's 31 assessed water bodies are classified as impaired (12 impaired). The top reported causes are ARSENIC, ZINC, BENTHIC MACROINVERTEBRATES. 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 Summit County?
EPA's Water Quality Portal records 14,008 measurements from 53 monitoring sites in Summit County over the past five years. The most frequently measured characteristic groups are Nutrient, Physical, 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 Summit County right now?
Summit County's primary USGS streamgage on the BLUE RIVER BELOW GREEN MOUNTAIN RESERVOIR, CO has a pipeline snapshot of 62.5 cubic feet per second — 14% of the long-term mean of 440.87 cfs. This is well below typical — often a signal of drought stress on source water. For the latest gauge feed, visit waterdata.usgs.gov.
How does Summit County water compare to the Colorado average?
Summit County's SDWIS water quality score of 54.0/100 is higher than the Colorado state average of 38.7. The average water quality grade across Colorado is F, based on data from 64 counties with available SDWIS data.
Is tap water safe to drink in Summit County?
Based on EPA SDWIS data, Summit County has a water quality grade of C (54.0/100). 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 Summit County have so many water violations?
Summit County has 8 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 Summit County rank for water quality in Colorado?
Summit County ranks #19 out of 64 counties in Colorado by SDWIS water quality score (1 = best). With a score of 54.0/100, 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

Jefferson County

Colorado

C

54.0

Water score

Montezuma County

Colorado

C

54.6

Water score

Weld County

Colorado

C

55.2

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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