waterbycounty
Federal water data

County water report

Grays Harbor County Water Report

Drinking-water compliance, watershed health, monitoring records, and river conditions for Grays Harbor County, Washington.

Water grade

C

Water score

53.6

State rank

#26

of 39

Health violations

9

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

38

59,178 recent measurements

Live streamflow

30%

CHEHALIS RIVER AT PORTER, WA

Water at a glance

Key Water Indicators for Grays Harbor County

EPA SDWIS

Safety Grade

C

Score: 53.6 / 100

EPA SDWIS

Active Violations

9

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

30% of mean

CHEHALIS RIVER AT PORTER, WA

EPA WQP

Monitoring Sites

38

59,178 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

9

Health-based violations

Violations per 100K served

11.7

Population-normalized SDWIS rate

Editorial analysis

Understanding Grays Harbor County’s Water

Drinking Water Quality Overview

EPA SDWIS

Grays Harbor County's drinking water earned a C grade, scoring 53.6 out of 100. Over the past five years, EPA SDWIS records 9 health-based violations — a pattern that public water utilities are required to disclose and correct.

River & Streamflow Status

USGS NWIS

USGS NWIS gauge data (as of 2026-05-14T11:45:00.000-07:00) puts CHEHALIS RIVER at 1.2k cfs — well below its long-term average at 30% 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. Grays Harbor County has moderate coverage with 38 active monitoring sites with 59,178 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 Grays Harbor County

Water Verdict

Grays Harbor County, Washington 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. The county's primary USGS gauge drains roughly 1,294 square miles of upstream watershed, giving local source waters a regional footprint. At the most recent USGS reading, local streamflow was below its historical mean at 30.1% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Grays Harbor County, Washington show 9 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 11.7 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: 59,178 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 Grays Harbor County meets baseline standards but the compliance record shows room for improvement, with a Grade C rating. Grays Harbor County's drinking-water compliance score is 53.6 out of 100. The violation rate for Grays Harbor County is 11.7 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. With 38 active water-quality monitoring sites in Grays Harbor County, data coverage is strong. A pipeline streamflow snapshot from the CHEHALIS RIVER gauge is also available on this page.

Regional Context

Grays Harbor County has poorer water quality than the average county in Washington. Its water score is 5.7 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 Grays Harbor County's water environment

Official EPA Resources for Grays Harbor County

EPA How's My Waterway

Interactive watershed health data for Grays Harbor County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Grays Harbor County

Consumer Confidence Reports (WA)

Annual water quality reports from utilities in Washington

Past 5 years

Water Quality Monitoring

Monitoring Sites

38

Active in the past 5 years

Measurements Recorded

59K

59,178 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).

Live USGS Streamgage

River & Stream Conditions

Current Discharge

1,220cfs

May 14, 6:45 PM UTC

vs Long-Term Average

30%

Well below typical

Primary Streamgage

CHEHALIS RIVER AT PORTER, WA

USGS site
12031000
Drainage area
1,294 sq mi
Long-term mean
4,051 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 Grays Harbor 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.

Try the full calculator →

Improve your water quality at home

Berkey filters remove 99.9%+ of contaminants from tap water.

Shop Berkey →

Sponsored

Test your tap water

Tap Score provides professional mail-in water testing.

Get Tested →

Frequently Asked Questions

What is the water quality in Grays Harbor County, Washington?
Grays Harbor County, Washington has a drinking-water quality grade of C with a score of 53.6/100, based on EPA SDWIS compliance data. The county has 9 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 Grays Harbor County?
Grays Harbor County has 9 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 much water-quality monitoring happens in Grays Harbor County?
EPA's Water Quality Portal records 59,178 measurements from 38 monitoring sites in Grays Harbor 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.
What's happening with rivers in Grays Harbor County right now?
Grays Harbor County's primary USGS streamgage on the CHEHALIS RIVER has a pipeline snapshot of 1,220 cubic feet per second — 30% of the long-term mean of 4,051.16 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 Grays Harbor County water compare to the Washington average?
Grays Harbor County's SDWIS water quality score of 53.6/100 is lower than the Washington state average of 59.3. The average water quality grade across Washington is D, based on data from 39 counties with available SDWIS data.
Is tap water safe to drink in Grays Harbor County?
Based on EPA SDWIS data, Grays Harbor 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 Grays Harbor County have so many water violations?
Grays Harbor County has 9 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 Grays Harbor County rank for water quality in Washington?
Grays Harbor County ranks #26 out of 39 counties in Washington 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

Klickitat County

Washington

C

53.5

Water score

Walla Walla County

Washington

C

53.3

Water score

Skamania County

Washington

C

54.0

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.

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

Explore more data for Grays Harbor County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsDisaster RiskWeatherCounty Score