Is tap water safe in Kennewick?

EPA SDWIS shows no active health-based violation in this profile's reporting window. That is not the same as proving every contaminant is absent, and federal data can lag state and utility records.

How hard is the water in Kennewick, WA?

Nearby USGS observations produce an estimate of 60.4 ppm (3.5 grains per gallon), classified as moderately hard. This is not a tap measurement.

Do I need a water softener in ZIP code 99336?

There is no high-hardness trigger in this profile. Confirm conditions with an at-home hardness test before purchasing equipment.

City water profile

Kennewick water quality

Compare local ZIP estimates, evidence quality, associated public systems, and compliance history for Kennewick, Washington.

Median indexed hardness

53PPM

2 indexed ZIPs

Range 45–60.4 PPM

State comparison: 51 PPM below
State hardness rank: #115 of 133
Matched utilities: 1
Active health records: 0

City summary

What the indexed records say

Kennewick has 2 published ZIP profiles across Benton County. The indexed median is 53 PPM, compared with 104 PPM across Washington.

Among the 133 Washingtoncities with an indexed median, Kennewick ranks #115from highest to lowest. Across all 189 state ZIP profiles, available estimates run from 20.6to 238 PPM.

The 45–60.4 PPM range shows how much the available ZIP estimates vary within the city label.

Hardness distribution

How local ZIP estimates compare

Soft1 ZIP

Moderately hard1 ZIP

Hard0 ZIPs

Very hard0 ZIPs

2 of 2 ZIP profiles have a hardness estimate. Bars count ZIP profiles, not households or laboratory samples.

Evidence quality

Distance, dates, and confidence

Median nearest distance: 14.7 miles
Profiles with evidence: 2/2

Confidence labels

High: 0Moderate: 2Low: 0

Observation window: Jan 19, 2016 to Jun 2, 2026.

ZIP directory

Water reports in Kennewick

Open a ZIP for site-level provenance and measurements.

ZIP code

99336

Moderately Hard

60.4 PPM

Nearest site: 14.7 mi
Confidence: Moderate

View full ZIP evidence →

ZIP code

99338

Soft

45 PPM

Nearest site: 11.2 mi
Confidence: Moderate

View full ZIP evidence →

Public water systems

Utilities associated with this city

Kennewick City Of

PWSID WA5338100

Surface water

System population served: 118,164
Last reported: Jun 19, 2026

A municipal system, in-state city, and served county all agree with this Census ZCTA.

Compliance history

What EPA records show

No active health-based violation appears among the associated systems in the represented EPA reporting quarter. This does not mean every contaminant was tested at every tap.

Record	System	Period	Status
Total Haloacetic Acids (HAA5)	WA5338100	Apr 1, 2023	Resolved
TTHM	WA5338100	Apr 1, 2023	Resolved

Practical next steps

Move from index to evidence

1. Open your ZIP. Check distance, dates, confidence, and the associated utility.
2. Read the current CCR. Confirm source water, detections, limits, ranges, and notices.
3. Test the tap when needed. Confirm health concerns or treatment sizing with the right method.

Continue comparing

Other Washington communities

Prosser

Benton County

151 PPM median

Richland

Benton County

73 PPM median

West Richland

Benton County

60 PPM median

Lynden

Whatcom County

50 PPM median

Aberdeen

Grays Harbor County

57 PPM median

Hoquiam

Grays Harbor County

57 PPM median

Search all 133 Washington cities →

Questions people ask

About water in Kennewick

Is the water hard?

The indexed city median is 53 PPM. Open the ZIP report to verify the distance and confidence behind that estimate.

Is the tap water safe?

Compliance history is utility-wide and cannot guarantee conditions at every tap. Check current notices and test when address-specific evidence is needed.

Do I need treatment?

Choose treatment only after confirming the problem at the property. A softener targets hardness; contaminant treatment requires a matching, verified performance claim.