Skip to content
TapBuff
ZIP

Missouri Valley Water Supply

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
2,678 people
Connections
1,260
Water source
Groundwater
Based in
Missouri Valley, IA
County
Harrison
Owner
Local government
The ZIP code it serves

51555

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 2025.

Total trihalomethanes (TTHM), haloacetic acids (HAA5), nitrate and fluoride: Iowa’s own results, samples taken from Jan. 21, 2020 to July 20, 2026, with EPA’s 2012 to 2019 file for earlier years.

Arsenic and chromium (total): EPA’s compliance monitoring file, samples taken from April 23, 2013 to Oct. 24, 2018. Newer results are in the utility’s annual water quality report.

Above the health goal2

Arsenic

Comes from the source

Above the health goal

2.2ppb

Highest yearly average, 2013 to 2018

2018, one sample: 1.6 ppb

Averaged by year, the highest was 2.2 ppb, in 2013: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2018, the latest year on file, its one sample was 1.6 ppb.

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

2.9ppb

90th percentile, 2023 to 2025

In the latest period, 9 in 10 homes sampled were at or below 2.9 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 limits4

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

29ppb

Highest yearly average, 2020 to 2026

2026, one sample: 27.9 ppb

Averaged by year, the highest was 29 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2026, the latest year on file, its one sample was 27.9 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 24.8 ppb, in 2017.

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

20.2ppb

Highest yearly average, 2020 to 2026

Averaged by year, the highest was 20.2 ppb, in 2026, below EPA’s legal limit of 60 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 15.4 ppb, in 2017.

What handles it

No certification claim covers this compound yet.

Nitrate

Comes from the source

Below EPA’s limits

1.7ppm

Highest sample; found in 9 of 9

2026, one sample: 1.2 ppm

The highest sample, in 2023, was 1.7 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its one sample was 1.2 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.8 ppm, in 2019.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.61ppm

Highest yearly average, 2020 to 2025

2025 average: 0.3 ppm

Averaged by year, the highest was 0.61 ppm, in 2024, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 1.0 ppm. In 2025, the latest year on file, its two samples averaged 0.3 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 0.88 ppm, in 2014.

What handles it

One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Chromium (total)

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

Violations since 2016

No health-based violations on file with EPA since 2016. There are 2 monitoring or reporting violations: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Total trihalomethanes (TTHM), haloacetic acids (HAA5), nitrate and fluoride results here are Iowa’s own from 2020 on, with EPA’s national file for 2012 to 2019. Arsenic and chromium (total) come from EPA’s file alone, which ends in 2019. Missouri Valley Water Supply’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; Iowa’s results run from Jan. 21, 2020 to July 20, 2026; EPA’s compliance samples are from April 23, 2013 to Oct. 24, 2018.

Testing your own tap

Missouri Valley Water Supply’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 Missouri Valley Water Supply serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Midwest Laboratories

    Omaha, NE · about 25 miles

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

    (402) 334-7770

  • Analytical & Consulting Services

    Sergeant Bluff, IA · about 60 miles

    Certified for bacteria, nitrate

    (712) 943-4888

  • Siouxland District Health Department

    Sioux City, IA · about 69 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (712) 234-3908

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 IA4344088. Rebuilt from EPA data on Oct. 18, 2026.

Towns it serves

Also in Harrison County

All Iowa utilities

What to do next