Highland Water District
What EPA’s and Washington’s records show in this utility’s water: nitrate, arsenic and other regulated chemicals, plus violations since 2016, with the certification that handles each result.
- Serves
- 3,121 people
- Connections
- 1,276
- Water source
- Surface water bought from another system
- Based in
- Monroe, WA
- County
- Snohomish
- Owner
- Local government
The ZIP code it serves
The short answer
Nothing in EPA’s and Washington’s records for this utility is above a health goal. That covers nitrate, arsenic and other regulated chemicals, not everything. No health-based violations on file since 2016.
What was found
Haloacetic acids (HAA5) and total trihalomethanes (TTHM): Washington’s own results, samples taken from March 5, 2020 to July 6, 2026, with EPA’s 2012 to 2019 file for earlier years.
Below EPA’s limits2
Haloacetic acids (HAA5)
Forms or is added in treatment
44.6ppb
Highest yearly average, 2020 to 2026
Averaged by year, the highest was 44.6 ppb, in 2026, below EPA’s legal limit of 60 ppb. Its highest single sample was 46.6 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 36 ppb, in 2017.
What handles it
No certification claim covers this compound yet.
Total trihalomethanes (TTHM)
Forms or is added in treatment
53.6ppb
Highest yearly average, 2020 to 2026
2026 average: 47.1 ppb
Averaged by year, the highest was 53.6 ppb, in 2020, below EPA’s legal limit of 80 ppb. Its highest single sample was 68.4 ppb. In 2026, the latest year on file, its two samples averaged 47.1 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 48.8 ppb, in 2015.
What handles it
- NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
- NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”
Violations since 2016
No health-based violations on file with EPA since 2016. There are 4 monitoring or reporting violations: a sample missed, late or not reported.
What this report can’t tell you
Everything else. Haloacetic acids (HAA5) and total trihalomethanes (TTHM) results here are Washington’s own from 2020 on, with EPA’s national file for 2012 to 2019. Highland Water District’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; Washington’s results run from March 5, 2020 to July 6, 2026.
Testing your own tap
The 3 labs Washington certifies closest to the area Highland Water District serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Everett Environmental Laboratory
Everett, WA · about 15 miles
Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics
OnSite Environmental, Inc.
Redmond, WA · about 16 miles
Certified for lead and copper, metals, minerals and other inorganics
Precision Analytical Laboratories, LLC
Everett, WA · about 18 miles
Certified for lead and copper, metals, minerals and other inorganics
Sources
- EPA UCMR 5 occurrence data, file of Oct. 15, 2026
- EPA SDWA bulk download (SDWIS federal data), 2026 Q3
- Washington State Department of Health, Office of Drinking Water, results from Jan. 1, 2020 to Sept. 29, 2026, read Oct. 8, 2026
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Washington State Department of Ecology, Lab Accreditation Program, environmental laboratories accredited for drinking water analyses, 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 WA5332850. Rebuilt from EPA data on Oct. 18, 2026.
What to do next
- Nothing here is above a health goalIn EPA’s and Washington’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 reportHighland Water District 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