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Stone Creek Estates Water Assn.

What EPA’s and Washington’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals; lead and copper; and violations since 2016, with the certification that handles each result.

Serves
62 people
Connections
22
Water source
Groundwater
Based in
Kent, WA
County
King
Owner
Private
Hardness
Soft
The ZIP code it serves

98038

The short answer

2 results are above the health goal. The worst: Lead, above the health goal. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2002 to 2023.

Arsenic, nitrate, chromium (total) and fluoride: Washington’s own results, samples taken from July 14, 2020 to June 15, 2026, with EPA’s 2012 to 2019 file for earlier years.

Haloacetic acids (HAA5) and total trihalomethanes (TTHM): EPA’s compliance monitoring file, samples taken from Aug. 31, 2016 to Aug. 31, 2016. Newer results are in the utility’s annual water quality report.

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

4.4ppb

90th percentile, 2021 to 2023

In the latest period, 9 in 10 homes sampled were at or below 4.4 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027. EPA’s health goal for lead is zero.

What handles it

Arsenic

Comes from the source

Above the health goal

1.6ppb

Highest yearly average, 2024

Averaged by year, the highest was 1.6 ppb, in 2024: below EPA’s legal limit of 10 ppb, but above its health goal of zero. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.6 ppb, in 2013.

What handles it

  • NSF/ANSI 58 look for “Arsenic (Pentavalent)<=50 ppb Reduction”
  • NSF/ANSI 53 look for “Arsenic (Pentavalent)<=50 ppb Reduction”

Below EPA’s limits1

Nitrate

Comes from the source

Below EPA’s limits

0.87ppm

Highest sample; found in 8 of 8

2026, one sample: 0.86 ppm

The highest sample, in 2024, was 0.87 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 0.86 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.96 ppm, in 2015.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
4 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)
  • Fluoride
  • Haloacetic acids (HAA5)
  • Total trihalomethanes (TTHM)

What handles it

A certification covers specific claims, not a whole standard. Look for these claims on the certifier’s listing, not the box. Wording varies a little: NSF writes “Lead Reduction,” WQA just “Lead.”

  • NSF/ANSI 53

    Claims: Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Lead, Arsenic

    Other certifiers’ wording: Arsenic (III) (50 ppb influent level)

  • NSF/ANSI 58

    Claims: Lead Reduction, Arsenic (Pentavalent)<=50 ppb Reduction

    For: Lead, Arsenic

    Other certifiers’ wording: Arsenic (Pentavalent)<=300 ppb Reduction; Arsenic (V) (300 ppb influent level)

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. How whole-house systems compare.

Filters with those claims on a certifier’s listing

Disclosure: TapBuff earns a commission if you buy through some links on this page. It does not change which standard or filter we name. As an Amazon Associate, TapBuff earns from qualifying purchases. How TapBuff makes money

Compare five-year costs

The best water filters for lead, ranked

The best reverse osmosis systems, ranked

Hardness

Soft, 55 mg/L (3.2 grains per gallon), at its one sampling point, in 2024.

Hardness is calcium and magnesium. EPA sets no limit for it: it shows up as scale on fixtures and in water heaters, and as soap that won’t lather. USGS calls water above 60 mg/L moderately hard, above 120 hard and above 180 very hard.

Softeners compared at 3.2 grains per gallon, salt includedSoftener or salt-free conditioner?Washington water hardness, utility by utility

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Revised Total Coliform RuleE. coli was confirmed in the water system.EPA: Maximum Contaminant Level Violation, E. coli (RTCR)Sept. 1, 2025 to Sept. 30, 2025—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 4 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Arsenic, nitrate, chromium (total) and fluoride results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Haloacetic acids (HAA5) and total trihalomethanes (TTHM) come from EPA’s file alone, which ends in 2019. Stone Creek Estates Water Assn.’s own annual report, which it must send you every year, has newer results for those and the contaminants this page does not show.

  • Your own plumbing. Lead results are the 90th percentile across homes the utility samples. Your home’s service line, solder and fixtures decide yours. A certified lab test is the only way to know.

  • What it means for your health. This page reports what the records show and EPA’s limits and goals; it is not medical advice. If you are worried about a health effect, talk to a doctor or your local health department.

  • Anything after the latest data. SDWIS data is from 2026 Q3; UCMR 5 didn’t sample this utility; Washington’s results run from July 14, 2020 to June 15, 2026; EPA’s compliance samples are from Aug. 31, 2016 to Aug. 31, 2016.

Testing your own tap

Stone Creek Estates Water Assn.’s results are for the water it sends out. What your own service line, solder and fixtures add shows up only in a test of your tap, by a lab Washington certifies.

The 3 labs Washington certifies closest to the area Stone Creek Estates Water Assn. serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Aqua Test, Incorporated

    Maple Valley, WA · under a mile

    Certified for bacteria, nitrate

    (425) 432-9360

  • AmTest Laboratories

    Renton, WA · about 13 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, disinfection byproducts

    (425) 885-1664

  • Analytical Resources, LLC

    Tukwila, WA · about 17 miles

    Certified for nitrate, lead and copper, metals, minerals and other inorganics

    (206) 695-6200

All 84 certified labs for Washington

Sources

PWSID WA5384530. Rebuilt from EPA data on Oct. 18, 2026.

Also in King County

All Washington utilities

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