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Federal water data

County water report

Washington County Water Report

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

Water grade

B

Water score

67.7

State rank

#8

of 36

Health violations

12

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

78

201,896 recent measurements

Live streamflow

24%

TUALATIN RIVER AT HWY 219 NEAR HILLSBORO, OR

Water at a glance

Key Water Indicators for Washington County

EPA SDWIS

Safety Grade

B

Score: 67.7 / 100

EPA SDWIS

Active Violations

12

5-year health-based lookback

EPA ATTAINS

Watershed Health

Not reported

Coverage varies by state

USGS NWIS

Streamflow Snapshot

24% of mean

TUALATIN RIVER AT HWY 219 NEAR HILLSBORO, OR

EPA WQP

Monitoring Sites

78

201,896 recent readings

Source: EPA SDWIS · Safe Drinking Water Information System

Drinking Water Compliance

Compliance grade

B

Based on EPA SDWIS compliance history.

Water score

Higher scores indicate cleaner recent compliance records.

67.7/100

Health violations

12

Health-based violations

Violations per 100K served

2.1

Population-normalized SDWIS rate

Data center water stress

Washington County has 39 facilities in the DCWSI dataset.

ByCounty's DCWSI ranks this county #33 nationally by combining its water score with mapped data center density.

DCWSIThe Data Center Water Stress Index: 60% the county's water-system stress plus 40% how concentrated data centers already are, scored 0-100. Higher means data-center density and water pressure overlap more here.

79.7

0-100 index

Facility count

39

97.6 density percentile

Discharge estimate

Not reported

EPA CWA fields where available

Water vs median

+17.7

Compared with US county median

Named operators

Oracle

Mapped facilities

  • Adobe Data Center

    Hillsboro

    OSM

  • Aligned DC - PDX-01

    Hillsboro · Aligned Data Centers

    OSM

  • Crane DC - Portland

    Forest Grove · Crane Data Centers Inc.

    OSM

  • Data Center

    Oregon Health & Science University

    OSM

  • Digital Fortress - Portland 2

    Beaverton · Digital Fortress, Inc

    OSM

  • Digital Fortress - Portland 3

    Beaverton · Digital Fortress, Inc

    OSM

33 more mapped facilities included in the county score.

See the Washington County data-center reportReview methodology

Data Center Water Budget Calculator

Estimate daily water use for a hypothetical facility in Washington County.

1 MW1,000 MW
40%100%
799K gallons/dayHigh Impact

Your facility would use 19.2% of this county's industrial water baseline. Verify water rights and long-term drought projections before committing.

19.2% of county industrial baseline3.36 Mgal/day remaining headroom

Based on USGS 2020 water-use data and EPA-standard cooling intensity constants. Not a substitute for site-specific water rights analysis.

Editorial analysis

Understanding Washington County’s Water

Drinking Water Quality Overview

EPA SDWIS

Washington County earns a B grade for drinking water quality, scoring 67.7 out of 100. Over the past five years, EPA SDWIS records 12 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 2026-05-14T11:30:00.000-07:00) puts TUALATIN RIVER at 233.0 cfs — well below its long-term average at 24% 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. Washington County has extensive coverage with 78 active monitoring sites with 201,896 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 Washington County

Water Verdict

Washington County, Oregon receives a fair water quality assessment with a grade of B and a score of 67.7 out of 100. The water supply meets baseline federal standards, but there may be periods of elevated contaminant levels or infrastructure concerns worth monitoring. The county's primary USGS gauge drains roughly 462 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 24.0% — worth watching in drier seasons.

Violation Context

EPA SDWIS records for Washington County, Oregon show 12 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 2.1 violations per 100,000 people served, this rate is relatively low compared to many U.S. counties. This compliance record sits alongside an unusually deep monitoring archive: 201,896 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 Washington County meets baseline safety standards, though the compliance record shows some violations worth watching. Washington County's drinking-water compliance score is 67.7 out of 100. The violation rate for Washington County is 2.1 per 100,000 people served. Running tap water for 30 seconds before drinking can reduce any localized lead exposure from household plumbing. Requesting your utility's most recent Consumer Confidence Report is the fastest way to identify which specific contaminants were flagged. With 78 active water-quality monitoring sites in Washington County, data coverage is strong. A pipeline streamflow snapshot from the TUALATIN RIVER gauge is also available on this page.

Regional Context

Washington County has better water quality than the average county in Oregon. Its water score is 23.1 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 Washington County's water environment

Official EPA Resources for Washington County

EPA How's My Waterway

Interactive watershed health data for Washington County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Washington County

Consumer Confidence Reports (OR)

Annual water quality reports from utilities in Oregon

Past 5 years

Water Quality Monitoring

Monitoring Sites

78

Active in the past 5 years

Measurements Recorded

202K

201,896 total readings

Most Measured

  • Physical
  • Nutrient
  • Organics, Pesticide

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

233cfs

May 14, 6:30 PM UTC

vs Long-Term Average

24%

Well below typical

Primary Streamgage

TUALATIN RIVER AT HWY 219 NEAR HILLSBORO, OR

USGS site
14206241
Drainage area
462 sq mi
Long-term mean
971 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 Washington 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 Washington County, Oregon?
Washington County, Oregon has a drinking-water quality grade of B with a score of 67.7/100, based on EPA SDWIS compliance data. The county has 12 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 Washington County?
Washington County has 12 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 Washington County?
EPA's Water Quality Portal records 201,896 measurements from 78 monitoring sites in Washington County over the past five years. The most frequently measured characteristic groups are Physical, Nutrient, Organics, Pesticide. 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 Washington County right now?
Washington County's primary USGS streamgage on the TUALATIN RIVER has a pipeline snapshot of 233 cubic feet per second — 24% of the long-term mean of 970.95 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 Washington County water compare to the Oregon average?
Washington County's SDWIS water quality score of 67.7/100 is higher than the Oregon state average of 44.6. The average water quality grade across Oregon is D, based on data from 36 counties with available SDWIS data.
Is tap water safe to drink in Washington County?
Based on EPA SDWIS data, Washington County has a water quality grade of B (67.7/100). 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).
Why does Washington County have so many water violations?
Washington County has 12 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 Washington County rank for water quality in Oregon?
Washington County ranks #8 out of 36 counties in Oregon by SDWIS water quality score (1 = best). With a score of 67.7/100, 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

Multnomah County

Oregon

B

66.8

Water score

Deschutes County

Oregon

C

60.1

Water score

Linn County

Oregon

C

53.8

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

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