City of Mahaska
What EPA’s and Kansas’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
- 44 people
- Connections
- 42
- Water source
- Groundwater
- Based in
- Mahaska, KS
- County
- Washington
- Owner
- Local government
- Hardness
- Hard
The ZIP code it serves
The short answer
Nothing in EPA’s and Kansas’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. 1 health-based violation since 2016.
What was found
Nitrate, fluoride, chromium (total), arsenic, haloacetic acids (HAA5), total trihalomethanes (TTHM) and uranium: Kansas’s own results, samples taken from March 2, 2020 to April 16, 2025, with EPA’s 2012 to 2019 file for earlier years.
Below EPA’s limits3
Nitrate
Comes from the source
5.3ppm
Highest sample; found in 1 of 8
2025: not found
The highest sample, in 2022, was 5.3 ppm, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, it wasn’t found in its one sample. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.37 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
1.2ppm
Highest yearly average, 2020 to 2023
2023, one sample: 1.2 ppm
Averaged by year, the highest was 1.2 ppm, in 2020, below EPA’s legal limit of 4.0 ppm. In 2023, the latest year on file, its one sample was 1.2 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 1.0 ppm, in 2017.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Chromium (total)
Comes from the source
2.8ppb
Highest yearly average, 2020 to 2023
2023, one sample: 1.5 ppb
Averaged by year, the highest was 2.8 ppb, in 2020, below EPA’s legal limit of 100 ppb. In 2023, the latest year on file, its one sample was 1.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 4.3 ppb, in 2017.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
5 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Arsenic
- Haloacetic acids (HAA5)
- Lead
- Total trihalomethanes (TTHM)
- Uranium
Hardness
Hard, 135 mg/L (7.9 grains per gallon), at its one sampling point, 2015 to 2023.
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.
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Revised Total Coliform Rule | Coliform results required a check of the system, and the check or its fixes were not done on time.EPA: Treatment Technique, Level 1 Assessment (RTCR) | May 28, 2024 | — | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 5 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Nitrate, fluoride, chromium (total), arsenic, haloacetic acids (HAA5), total trihalomethanes (TTHM) and uranium results here are Kansas’s own from 2020 on, with EPA’s national file for 2012 to 2019. City of Mahaska’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; Kansas’s results run from March 2, 2020 to April 16, 2025.
Testing your own tap
The 2 labs Kansas certifies closest to the area City of Mahaska serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
LandIntel Solutions, LLC
Scandia, KS · about 28 miles
Certified for bacteria
Irwin Army Community Hospital-Water Laboratory-PH-EH
Fort Riley, KS · about 66 miles
Certified for bacteria
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- Kansas Department of Health and Environment, Public Water Supply Section, results from Jan. 2, 2020 to Sept. 16, 2026, read Oct. 18, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Kansas Department of Health and Environment, drinking water labs, as listed in TNI LAMS, read Oct. 13, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Hardness: Kansas Department of Health and Environment, Public Water Supply Section, results from April 26, 2015 to March 12, 2023, read Oct. 18, 2026
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID KS2020102. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Nothing here is above a health goalIn EPA’s and Kansas’s records for this utility. They don’t cover everything, which is why the next step matters.Every contaminant TapBuff tracks
- Get the utility’s own reportCity of Mahaska must send you a water quality report every year. It covers contaminants this page does not show.How to read it
- Test your own tap for leadYour service line, solder and fixtures decide the lead at your faucet, not the utility’s average.Lead in your water: what to do
- Decide if you want a filter at allA filter for taste or chlorine is a preference, not a need. The standards say what each kind can do.NSF/ANSI standards, decoded