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City of Rock Island Water Dept

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
3,226 people
Connections
540
Water source
Groundwater
Based in
Rock Island, WA
County
Douglas
Owner
Local government
Hardness
Very hard
The ZIP code it serves

98850

The short answer

2 results are above the health goal. The worst: Arsenic, above the health goal. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2003 to 2024.

Arsenic, nitrate, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total): Washington’s own results, samples taken from Aug. 27, 2020 to Aug. 24, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

2.3ppb

Highest yearly average, 2023 to 2025

2025, one sample: 1.9 ppb

Averaged by year, the highest was 2.3 ppb, in 2023: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2025, the latest year on file, its one sample was 1.9 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.4 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”

Lead

Comes from pipes, often your own

Above the health goal

1.0ppb

90th percentile, 2022 to 2024

In the latest period, 9 in 10 homes sampled were at or below 1.0 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

Below EPA’s limits5

Nitrate

Comes from the source

Below EPA’s limits

10.1ppm

Highest sample; found in 14 of 15

2026, one sample: 3.8 ppm

The highest sample, in 2025, was 10.1 ppm, which EPA rounds to 10 ppm to compare: at its legal limit of 10 ppm, not above it. In 2026, the latest year on file, its one sample was 3.8 ppm. EPA recorded no violation for nitrate at this utility since 2020. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 5.8 ppm, in 2019.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

17.6ppb

Highest yearly average, 2020 to 2026

2026, one sample: 10.4 ppb

Averaged by year, the highest was 17.6 ppb, in 2025, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its one sample was 10.4 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 11.4 ppb, in 2019.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

2.7ppb

Highest yearly average, 2020 to 2026

2026: not found

Averaged by year, the highest was 2.7 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2026, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 2.5 ppb, in 2016.

What handles it

No certification claim covers this compound yet.

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.17ppm

Highest yearly average, 2025

Averaged by year, the highest was 0.17 ppm, in 2025, below EPA’s legal limit of 4.0 ppm. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.44 ppm, in 2012.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

1.4ppb

Highest yearly average, 2025

Averaged by year, the highest was 1.4 ppb, in 2025, below EPA’s legal limit of 100 ppb. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.7 ppb, in 2013.

What handles it

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

    For: Arsenic, Lead

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

  • NSF/ANSI 58

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

    For: Arsenic, Lead

    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 reverse osmosis systems, ranked

The best water filters for lead, ranked

Hardness

Very hard, 290 mg/L (17 grains per gallon), at its one sampling point, in 2025.

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 17 grains per gallon, salt includedSoftener or salt-free conditioner?Washington water hardness, utility by utility

Violations since 2016

No health-based violations on file with EPA since 2016. There are 4 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Arsenic, nitrate, total trihalomethanes (TTHM), haloacetic acids (HAA5), fluoride and chromium (total) results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of Rock Island Water Dept’s own annual report, which it must send you every year, has 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 Aug. 27, 2020 to Aug. 24, 2026.

Testing your own tap

City of Rock Island Water Dept’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 City of Rock Island Water Dept serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Anatek Labs, Inc - Wenatchee

    Wenatchee, WA · about 15 miles

    Certified for bacteria

    (509) 701-8362

  • Soiltest Farm Consultants, Inc. Laboratory

    Moses Lake, WA · about 38 miles

    Certified for nitrate, minerals and other inorganics

    (509) 765-1622

  • AV Labs, Inc

    Othello, WA · about 54 miles

    Certified for bacteria

    (509) 488-2468

All 84 certified labs for Washington

Sources

PWSID WA5373401. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Douglas County

All Washington utilities

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