Lake Thunderhead
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
- 585 people
- Connections
- 652
- Water source
- Surface water bought from another system
- Based in
- Unionville, MO
- County
- Putnam
- Owner
- Private
The ZIP code it serves
The short answer
Nothing in EPA’s and CDC’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, plus lead and copper, not everything. 6 health-based violations since 2016.
What was found
Total trihalomethanes (TTHM) and haloacetic acids (HAA5): 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.
Below EPA’s limits2
Total trihalomethanes (TTHM)
Forms or is added in treatment
72ppb
Highest yearly average, 2020 to 2023
2023 average: 39.5 ppb
Averaged by year, the highest was 72 ppb, in 2020, below EPA’s legal limit of 80 ppb. In 2023, the latest year on file, it averaged 39.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 125 ppb, in 2015, and EPA recorded violations in 2015 and 2016.
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
53.7ppb
Highest yearly average, 2020 to 2023
2023 average: 15.9 ppb
Averaged by year, the highest was 53.7 ppb, in 2020, below EPA’s legal limit of 60 ppb. In 2023, the latest year on file, it averaged 15.9 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 92.8 ppb, in 2015, and EPA recorded violations in 2015 and 2016.
What handles it
No certification claim covers this compound yet.
One compound tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Lead
Violations since 2016
| Contaminant or rule | Type | Period | Measured | Status |
|---|---|---|---|---|
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2016 to Sept. 30, 2016 | 102 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | July 1, 2016 to Sept. 30, 2016 | 72 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2016 to June 30, 2016 | 72 UG/L | Resolved |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | April 1, 2016 to June 30, 2016 | 117 UG/L | Resolved |
| Total Haloacetic Acids (HAA5) | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2016 to March 31, 2016 | 81 UG/L | Resolved |
| TTHM | The running average was above the legal limit.EPA: Maximum Contaminant Level Violation, Average | Jan. 1, 2016 to March 31, 2016 | 124 UG/L | Resolved |
| Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 15 monitoring or reporting violations not shown. | ||||
What this report can’t tell you
Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Missouri’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Lake Thunderhead’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; CDC’s yearly averages for Missouri cover 2020 to 2023.
Testing your own tap
The 3 labs Missouri certifies closest to the area Lake Thunderhead serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Microbac Laboratories Inc.-Centerville
Centerville, IA · about 16 miles
Certified for bacteria
Rathbun Regional Water Association
Centerville, IA · about 16 miles
Certified for bacteria
North Central Missouri Regional Water Commission
Milan, MO · about 23 miles
Certified for bacteria
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 MissouriSources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- CDC Environmental Public Health Tracking Network, yearly averages Missouri supplied to CDC, 2020 to 2023, read Oct. 8, 2026. TapBuff’s comparisons with EPA’s limits are its own, not CDC’s or Missouri’s.
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Missouri DNR, certified microbiological and chemical laboratories, 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 MO2036165. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Nothing here is above a health goalIn EPA’s and CDC’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 reportLake Thunderhead 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