Town of Lyons

What EPA’s and Colorado’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: 2,990 people
Connections: 962
Water source: Surface water bought from another system
Based in: Lyons, CO
County: Boulder
Owner: Local government

The ZIP code it serves

80540

The short answer

Nothing in EPA’s and Colorado’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

Total trihalomethanes (TTHM) and haloacetic acids (HAA5): Colorado’s own results, samples taken from Jan. 7, 2020 to July 9, 2026, with EPA’s 2012 to 2019 file for earlier years.

Below EPA’s limits2

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

47.3ppb

Highest yearly average, 2020 to 2026

2026 average: 29.8 ppb

Averaged by year, the highest was 47.3 ppb, in 2021, below EPA’s legal limit of 80 ppb. Its highest single sample was 60.1 ppb. In 2026, the latest year on file, its five samples averaged 29.8 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 48.5 ppb, in 2018.

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

22ppb

Highest yearly average, 2020 to 2026

2026 average: 21.5 ppb

Averaged by year, the highest was 22 ppb, in 2022, below EPA’s legal limit of 60 ppb. Its highest single sample was 27.5 ppb. In 2026, the latest year on file, its five samples averaged 21.5 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 29.6 ppb, in 2014.

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

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

What this report can’t tell you

Everything else. Total trihalomethanes (TTHM) and haloacetic acids (HAA5) results here are Colorado’s own from 2020 on, with EPA’s national file for 2012 to 2019. Town of Lyons’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; Colorado’s results run from Jan. 7, 2020 to July 9, 2026.

Testing your own tap

Town of Lyons’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 Colorado certifies.

The 3 labs Colorado certifies closest to the area Town of Lyons serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

EAnalytics Laboratory
Loveland, CO · about 23 miles
Certified for bacteria
M.M.S Environmental Laboratories
Fort Collins, CO · about 23 miles
Certified for bacteria
Technology Laboratory, Inc.
Fort Collins, CO · about 23 miles
Certified for nitrate, minerals and other inorganics, organic chemicals