Henderson Water Department

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: 144 people
Connections: 93
Water source: Groundwater
Based in: Henderson, IA
County: Mills
Owner: Local government

The ZIP code it serves

51541

The short answer

Nothing in EPA’s and Iowa’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. No health-based violations on file since 2016.

What was found

Nitrate, total trihalomethanes (TTHM), fluoride, arsenic, chromium (total) and haloacetic acids (HAA5): Iowa’s own results, samples taken from Jan. 21, 2020 to July 15, 2026, with EPA’s 2012 to 2019 file for earlier years.

Below EPA’s limits3

Nitrate

Comes from the source

Below EPA’s limits

4.9ppm

Highest sample; found in 27 of 27

2026 average: 1.4 ppm

The highest sample, in 2020, was 4.9 ppm, below EPA’s legal limit of 10 ppm. In 2026, the latest year on file, its three samples averaged 1.4 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 5.8 ppm, in 2016.

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

7.9ppb

Highest yearly average, 2022 to 2025

2025, one sample: 3.4 ppb

Averaged by year, the highest was 7.9 ppb, in 2022, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, its one sample was 3.4 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 31 ppb, in 2016.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.36ppm

Highest yearly average, 2023

Averaged by year, the highest was 0.36 ppm, in 2023, 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 0.42 ppm, in 2014.

What handles it

NSF/ANSI 58 look for “Fluoride Reduction”
NSF/ANSI 53 look for “Fluoride”

4 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

Violations since 2016

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

What this report can’t tell you

Everything else. Nitrate, total trihalomethanes (TTHM), fluoride, arsenic, chromium (total) and haloacetic acids (HAA5) results here are Iowa’s own from 2020 on, with EPA’s national file for 2012 to 2019. Henderson Water Department’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. 21, 2020 to July 15, 2026.

Testing your own tap

Henderson Water Department’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 lab Iowa certifies closest to the area Henderson Water Department 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 37 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics
(402) 334-7770

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