Hawthorne Terrace Assoc
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
- 156 people
- Connections
- 50
- Water source
- Groundwater
- Based in
- Danbury, CT
- County
- Fairfield
- Owner
- Local government
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. No health-based violations on file since 2016.
What was found
Copper: EPA’s file records a utility’s copper only when it exceeds the action level. The last here was 1.6 ppm, for the period ending June 30, 2014. None since is on file, so it is not counted as a current finding.
Nitrate, arsenic and uranium: Connecticut’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.
Chromium (total) and fluoride: EPA’s compliance monitoring file, samples taken from April 16, 2013 to May 16, 2019. Newer results are in the utility’s annual water quality report.
Below EPA’s limits3
Nitrate
Comes from the source
1.4ppm
Highest yearly average, 2020 to 2023
2023 average: 1.4 ppm
Averaged by year, the highest was 1.4 ppm, in 2021, below EPA’s legal limit of 10 ppm. In 2023, the latest year on file, it averaged 1.4 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 1.4 ppm, in 2016.
What handles it
- NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
- NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”
Chromium (total)
Comes from the source
2.4ppb
Highest yearly average, 2013 to 2019
2019: not found
Averaged by year, the highest was 2.4 ppb, in 2013, below EPA’s legal limit of 100 ppb. Its highest single sample was 4.8 ppb. In 2019, the latest year on file, it wasn’t found in any of its two samples.
What handles it
- NSF/ANSI 58 look for “Chromium (Hexavalent) Reduction”
- NSF/ANSI 53 look for “Chromium Reduction”
Fluoride
Forms or is added in treatment
0.06ppm
Highest yearly average, 2013 to 2019
2019 average: 0.06 ppm
Averaged by year, the highest was 0.06 ppm, in 2018, below EPA’s legal limit of 4.0 ppm. In 2019, the latest year on file, its two samples averaged 0.06 ppm.
What handles it
- NSF/ANSI 58 look for “Fluoride Reduction”
- NSF/ANSI 53 look for “Fluoride”
3 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
- Arsenic
- Lead
- Uranium
Violations since 2016
No health-based violations on file with EPA since 2016. There are 5 monitoring or reporting violations: a sample missed, late or not reported.
What this report can’t tell you
Everything else. Nitrate, arsenic and uranium results here are Connecticut’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Chromium (total) and fluoride come from EPA’s file alone, which ends in 2019. Hawthorne Terrace Assoc’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; CDC’s yearly averages for Connecticut cover 2020 to 2023; EPA’s compliance samples are from April 16, 2013 to May 16, 2019.
Testing your own tap
The 3 labs Connecticut certifies closest to the area Hawthorne Terrace Assoc serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
ALS Environmental - Newtown
Newtown, CT · about 9 miles
Certified for bacteria, nitrate, metals, minerals and other inorganics, organic chemicals, radioactivity
South Norwalk Electric & Water Laboratory
Wilton, CT · about 15 miles
Certified for bacteria, nitrate, minerals and other inorganics
Aquarion Water Trap Falls Water Quality Lab
Shelton, CT · about 19 miles
Certified for bacteria
Sources
- 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 Connecticut supplied to CDC, 2020 to 2023, read Oct. 8, 2026. TapBuff’s comparisons with EPA’s limits are its own, not CDC’s or Connecticut’s.
- EPA Six-Year Review 4 compliance monitoring data, 2012 to 2019, file of Feb. 5, 2024
- Certified labs: Connecticut DPH, approved commercial laboratories certified to test drinking water, 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 CT0340151. 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 reportHawthorne Terrace Assoc 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
- 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