Cosmos
What EPA’s and Minnesota’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
- 513 people
- Connections
- 243
- Water source
- Groundwater
- Based in
- Cosmos, MN
- County
- Meeker
- Owner
- Local government
The ZIP code it serves
The short answer
1 result is above EPA’s legal limit. The worst: Arsenic, above the legal limit. 4 health-based violations since 2016.
What handles itWhat was found
Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate: Minnesota’s yearly summaries per water system, 2023 to 2025, with EPA’s 2012 to 2019 file for earlier years.
Fluoride and chromium (total): EPA’s compliance monitoring file, samples taken from Jan. 25, 2012 to July 25, 2019. Newer results are in the utility’s annual water quality report.
Above the legal limit1
Arsenic
Comes from the source
7.6ppb
Highest yearly average, 2023 to 2025
2025 average: 6.5 ppb
Averaged by year, the highest was 7.6 ppb, in 2024: below EPA’s legal limit of 10 ppb, but above its health goal of zero. In 2025, the latest year on file, it averaged 6.5 ppb. EPA judges this limit at each sampling point, and recorded a violation for arsenic at this utility in 2021. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 9.4 ppb, in 2017.
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 limits4
Fluoride
Forms or is added in treatment
1.2ppm
Highest yearly average, 2012 to 2019
2019 average: 1 ppm
Averaged by year, the highest was 1.2 ppm, in 2015, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 1.5 ppm. In 2019, the latest year on file, its three samples averaged 1 ppm.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
Total trihalomethanes (TTHM)
Forms or is added in treatment
5.6ppb
Highest yearly average, 2024 to 2025
2025 average: 5.1 ppb
Averaged by year, the highest was 5.6 ppb, in 2024, below EPA’s legal limit of 80 ppb. In 2025, the latest year on file, it averaged 5.1 ppb.
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
3.1ppb
Highest yearly average, 2024 to 2025
2025: not found
Averaged by year, the highest was 3.1 ppb, in 2024, below EPA’s legal limit of 60 ppb. In 2025, the latest year on file, it wasn’t found.
What handles it
No certification claim covers this compound yet.
Nitrate
Comes from the source
0.3ppm
Highest yearly average, 2023 to 2025
2025: not found
Averaged by year, the highest was 0.3 ppm, in 2023, below EPA’s legal limit of 10 ppm. In 2025, the latest year on file, it wasn’t found. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 0.37 ppm, in 2014.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Chromium (total)
- Lead
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
Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Oct. 1, 2021 to Dec. 31, 2021 | 0.021 MG/L | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2021 to Sept. 30, 2021 | 0.025 MG/L | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2021 to June 30, 2021 | 0.023 MG/L | Resolved |
| Arsenic | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2021 to March 31, 2021 | 0.017 MG/L | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. | ||||
What this report can’t tell you
Everything else. Arsenic, total trihalomethanes (TTHM), haloacetic acids (HAA5) and nitrate results here are Minnesota’s own yearly summaries from 2023 on, with EPA’s national file for 2012 to 2019. Fluoride and chromium (total) come from EPA’s file alone, which ends in 2019. Cosmos’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; Minnesota’s yearly summaries cover 2023 to 2025; EPA’s compliance samples are from Jan. 25, 2012 to July 25, 2019.
Testing your own tap
The 3 labs Minnesota certifies closest to the area Cosmos serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Minnesota Valley Testing Laboratories, Inc.
New Ulm, MN · about 46 miles
Certified for bacteria, nitrate, lead and copper, metals
Engel Water Testing, Inc.
Minnetrista, MN · about 49 miles
Certified for bacteria
Traut Water Analysis Lab
St. Joseph, MN · about 53 miles
Certified for bacteria, nitrate
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- Minnesota Department of Health, Minnesota Public Health Data Access, results from Jan. 1, 2023 to Dec. 31, 2025, read Oct. 8, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Minnesota Department of Health, accredited labs in Minnesota accepting drinking water samples from private well users, read Oct. 10, 2026; distances from the Census 2020 ZIP code tabulation area gazetteer
- Limits and goals: each contaminant’s page, with its EPA source.
- How this page is built: methodology.
PWSID MN1470011. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Read up on ArsenicWhat each one does to health, where it comes from, and the certification claim that addresses it.About Arsenic
- Get the utility’s own reportCosmos must send you a water quality report every year. It covers contaminants this page does not show, and has newer results than EPA’s national file for the ones here that come from it.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
- Compare certified filtersWhat the filters certified for these results cost over five years, cartridges included.Compare five-year costs