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Walnut Grove MHP

What EPA’s and CDC’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
210 people
Connections
50
Water source
Groundwater
Based in
Irondale, MO
County
St. Francois
Owner
Private
The ZIP code it serves

63640

The short answer

1 result is 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

Arsenic and nitrate: Missouri’s yearly averages per water system, as CDC’s Environmental Public Health Tracking Network publishes them, 2020 to 2023, with EPA’s 2012 to 2019 file for earlier years.

Fluoride, chromium (total) and uranium: EPA’s compliance monitoring file, samples taken from May 27, 2014 to Dec. 10, 2019. Newer results are in the utility’s annual water quality report.

Above the health goal1

Arsenic

Comes from the source

Above the health goal

1.5ppb

Highest yearly average, 2020 to 2023

2023 average: 1.0 ppb

Averaged by year, the highest was 1.5 ppb, in 2020: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2023, the latest year on file, it averaged 1.0 ppb.

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 limits3

Nitrate

Comes from the source

Below EPA’s limits

0.96ppm

Highest yearly average, 2020 to 2023

2023 average: 0.07 ppm

Averaged by year, the highest was 0.96 ppm, in 2020, below EPA’s legal limit of 10 ppm. In 2023, the latest year on file, it averaged 0.07 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.0 ppm, in 2014.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.18ppm

Highest yearly average, 2014 to 2017

Averaged by year, the highest was 0.18 ppm, in 2017, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file.

What handles it

Chromium (total)

Comes from the source

Below EPA’s limits

2.4ppb

Highest yearly average, 2014 to 2017

Averaged by year, the highest was 2.4 ppb, in 2017, below EPA’s legal limit of 100 ppb. That was also the latest year on file.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Lead
  • Uranium

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

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

  • NSF/ANSI 58

    Claim: Arsenic (Pentavalent)<=50 ppb Reduction

    For: Arsenic

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

At the tap, or for the whole house?

These come with the water itself, so a whole-house system certified for the same claims treats every tap and shower. A filter at the tap treats drinking water for much less. 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

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Violations since 2016

No health-based violations on file with EPA since 2016.

What this report can’t tell you

  • Everything else. Arsenic and nitrate results here are Missouri’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Fluoride, chromium (total) and uranium come from EPA’s file alone, which ends in 2019. Walnut Grove MHP’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; CDC’s yearly averages for Missouri cover 2020 to 2023; EPA’s compliance samples are from May 27, 2014 to Dec. 10, 2019.

Testing your own tap

Walnut Grove MHP’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 Missouri certifies.

The 3 labs Missouri certifies closest to the area Walnut Grove MHP serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Eastern Missouri Water Lab

    Lonedell, MO · about 44 miles

    Certified for bacteria

    (636) 775-2889

  • Environmental Analysis South

    Jackson, MO · about 46 miles

    Certified for bacteria

    (573) 204-8817

  • EMSL Analytical Inc.-St. Louis

    St. Louis, MO · about 55 miles

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

    (314) 577-0150

Missouri State Public Health Laboratory: Coliform and E. coli testing for private wells and other private drinking water sources, in kits from your local public health agency. A free state courier can carry the sample to the lab overnight. The handling fee is $10, by check or money order. Private Drinking Water Bacteriological Testing, Missouri Department of Health and Senior Services.

All 64 certified labs for Missouri

Sources

PWSID MO4041308. Rebuilt from EPA data on Oct. 18, 2026.

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