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Federal water data

County water report

Yakima County Water Report

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

Water grade

B

Water score

62.8

State rank

#20

of 39

Health violations

12

EPA SDWIS, 5-year lookback

Watershed impaired

Not reported

EPA ATTAINS coverage varies by state

Monitoring sites

176

57,484 recent measurements

Live streamflow

No gauge

YAKIMA RIVER AT MABTON, WA

Water at a glance

Key Water Indicators for Yakima County

EPA SDWIS

Safety Grade

B

Score: 62.8 / 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

No gauge

YAKIMA RIVER AT MABTON, WA

EPA WQP

Monitoring Sites

176

57,484 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.

62.8/100

Health violations

12

Health-based violations

Violations per 100K served

4.8

Population-normalized SDWIS rate

Editorial analysis

Understanding Yakima County’s Water

Drinking Water Quality Overview

EPA SDWIS

Yakima County earns a B grade for drinking water quality, scoring 62.8 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.

Monitoring Network

EPA WQP

EPA's Water Quality Portal (WQP) aggregates monitoring data from federal, state, and tribal agencies. Yakima County has extensive coverage with 176 active monitoring sites with 57,484 recent measurements on record. Predominant monitoring categories include organics, pesticide 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 Yakima County

Water Verdict

Yakima County receives a fair water quality assessment with a grade of B and a score of 62.8 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

Yakima County has recorded 12 health-based violations, indicating multiple instances where federal contaminant limits or treatment requirements were not met. At 4.8 violations per 100,000 people served, this rate is moderate and suggests recurring water quality challenges.

Consumer Guidance

Tap water in Yakima County meets baseline safety standards, though the compliance record shows some violations worth watching. Yakima County's drinking-water compliance score is 62.8 out of 100. The violation rate for Yakima County is 4.8 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 176 active water-quality monitoring sites in Yakima County, data coverage is strong. A pipeline streamflow snapshot from the YAKIMA RIVER gauge is also available on this page.

Regional Context

Yakima County has water quality close to the average county in Washington. Its water score is within 3.5 points of the state average, meaning its overall water system performance is broadly representative of Washington as a whole.

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 Yakima County's water environment

Official EPA Resources for Yakima County

EPA How's My Waterway

Interactive watershed health data for Yakima County

EPA ECHO: Drinking Water Systems

Search water utilities and violation records for Yakima County

Consumer Confidence Reports (WA)

Annual water quality reports from utilities in Washington

Past 5 years

Water Quality Monitoring

Monitoring Sites

176

Active in the past 5 years

Measurements Recorded

57K

57,484 total readings

Most Measured

  • Organics, Pesticide
  • Physical
  • Not Assigned

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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Filter Cost

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Safety Grade for Yakima 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 Yakima County, Washington?
Yakima County, Washington has a drinking-water quality grade of B with a score of 62.8/100, 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 Yakima County?
Yakima 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 Yakima County?
EPA's Water Quality Portal records 57,484 measurements from 176 monitoring sites in Yakima County over the past five years. The most frequently measured characteristic groups are Organics, Pesticide, Physical, Not Assigned. 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 Yakima County water compare to the Washington average?
Yakima County's SDWIS water quality score of 62.8/100 is higher 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 Yakima County?
Based on EPA SDWIS data, Yakima County has a water quality grade of B (62.8/100). 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 Yakima County have so many water violations?
Yakima 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 Yakima County rank for water quality in Washington?
Yakima County ranks #20 out of 39 counties in Washington by SDWIS water quality score (1 = best). With a score of 62.8/100, 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

Clallam County

Washington

B

63.0

Water score

Mason County

Washington

C

62.2

Water score

Spokane County

Washington

B

63.8

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.

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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