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Dawson Water Works

What EPA’s and Iowa’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
116 people
Connections
81
Water source
Groundwater
Based in
Dawson, IA
County
Dallas
Owner
Local government
The ZIP code it serves

50066

The short answer

2 results are above EPA’s legal limit. The worst: Nitrate, above the legal limit. 7 health-based violations since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2024.

Nitrate, fluoride, arsenic, chromium (total), haloacetic acids (HAA5) and total trihalomethanes (TTHM): Iowa’s own results, samples taken from Jan. 15, 2020 to Sept. 28, 2026, with EPA’s 2012 to 2019 file for earlier years.

Above the legal limit2

Nitrate

Comes from the source

Above the legal limit

12ppm

Highest sample; found in 36 of 36

2026 average: 10.6 ppm

From 2025 to 2026, seven samples were above EPA’s legal limit of 10 ppm, the highest 12 ppm in 2026. The next sample at the same point, within 30 days, kept the average above the limit for two; five have no follow-up sample on file within 30 days. That was also the latest year on file, and its nine samples averaged 10.6 ppm, above the limit. EPA recorded violations for nitrate at this utility in 2025 and 2026. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 6.4 ppm, in 2017.

What handles it

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

Copper

Comes from pipes, often your own

Above the action level

1.5ppm

90th percentile, 2022 to 2024

In the latest period, 9 in 10 homes sampled were at or below 1.5 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Below EPA’s limits1

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.2ppm

Highest yearly average, 2022

Averaged by year, the highest was 0.2 ppm, in 2022, below EPA’s legal limit of 4.0 ppm. That is the only year on file.

What handles it

5 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • Chromium (total)
  • Haloacetic acids (HAA5)
  • Lead
  • 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: Nitrate/Nitrite (30 ppm challenge), Copper Reduction

    For: Nitrate, Copper

  • NSF/ANSI 58

    Claims: Nitrate/Nitrite Reduction, Copper Reduction

    For: Nitrate, Copper

    Other certifiers’ wording: Nitrate

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

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The best reverse osmosis systems, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleJune 1, 2026 to June 30, 202611 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMay 1, 2026 to May 31, 202611 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleApril 1, 2026 to April 30, 202612 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleMarch 1, 2026 to March 31, 202612 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleFeb. 1, 2026 to Feb. 28, 202611 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleDec. 1, 2025 to Dec. 31, 202511 MG/LArchived
NitrateA sample was above the legal limit, for a contaminant judged one sample at a time.EPA: Maximum Contaminant Level Violation, Single SampleOct. 1, 2025 to Oct. 31, 202511 MG/LArchived
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 10 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Nitrate, fluoride, arsenic, chromium (total), haloacetic acids (HAA5) and total trihalomethanes (TTHM) results here are Iowa’s own from 2020 on, with EPA’s national file for 2012 to 2019. Dawson Water Works’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; Iowa’s results run from Jan. 15, 2020 to Sept. 28, 2026.

Testing your own tap

Dawson Water Works’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 Iowa certifies.

The 3 labs Iowa certifies closest to the area Dawson Water Works serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • State Hygienic Laboratory - Ankeny

    Ankeny, IA · about 31 miles

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

    (515) 725-1600

  • AgSource

    Ellsworth, IA · about 51 miles

    Certified for bacteria, nitrate, metals, minerals and other inorganics

    (515) 297-8103

  • Microbac Laboratories - Newton

    Newton, IA · about 62 miles

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

    (641) 792-8451

State Hygienic Laboratory at the University of Iowa: Through the Grants-to-Counties program, private well owners in participating counties can have their water tested for total coliform bacteria and nitrate. Start with the county sanitarian at your county health department. No cost in a participating county. The Grants-to-Counties Program, State Hygienic Lab at the University of Iowa.

All 36 certified labs for Iowa

Sources

PWSID IA2525010. Rebuilt from EPA data on Oct. 18, 2026.

Also in Dallas County

All Iowa utilities

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