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Twin Lakes Water Co., Inc.

What EPA’s and New York’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
366 people
Connections
91
Water source
Groundwater
Based in
Lewisboro (T), NY
County
Westchester
Owner
Private
The ZIP code it serves

10590

The short answer

1 result is above EPA’s legal limit, and 1 more is above the health goal. The worst: Copper, above the action level. No health-based violations on file since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 2003 to 2024.

Uranium, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and arsenic: New York’s yearly summaries per water system, 2020 to 2024, with EPA’s 2012 to 2019 file for earlier years.

Chromium (total) and fluoride: EPA’s compliance monitoring file, samples taken from Sept. 25, 2013 to Feb. 22, 2018. Newer results are in the utility’s annual water quality report.

Above the legal limit1

Copper

Comes from pipes, often your own

Above the action level

1.4ppm

90th percentile, 2024

In the latest period, 9 in 10 homes sampled were at or below 1.4 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Above the health goal1

Uranium

Comes from the source

Above the health goal

16.9ppb

Highest yearly average, 2020 to 2023

2023 average: 0.022 ppb

Averaged by year, the highest was 16.9 ppb, in 2020: below EPA’s legal limit of 30 ppb, but above its health goal of zero. In 2023, the latest year on file, it averaged 0.022 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 31.2 ppb, in 2014.

What handles it

Below EPA’s limits5

Total trihalomethanes (TTHM)

Forms or is added in treatment

Below EPA’s limits

26.5ppb

Highest yearly average, 2020 to 2024

Averaged by year, the highest was 26.5 ppb, in 2024, below EPA’s legal limit of 80 ppb. Its highest single sample was 31 ppb. That was also the latest year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 20.2 ppb, in 2018.

What handles it

  • NSF/ANSI 53 look for “Trihalomethanes (TTHM) Reduction”
  • NSF/ANSI 58 look for “Trihalomethanes (TTHM) Reduction”

Nitrate

Comes from the source

Below EPA’s limits

3.0ppm

Highest sample; found in 5 of 5

2024 average: 1.5 ppm

The highest sample, in 2020, was 3.0 ppm, below EPA’s legal limit of 10 ppm. In 2024, the latest year on file, it averaged 1.5 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 3.2 ppm, in 2012.

What handles it

  • NSF/ANSI 58 look for “Nitrate/Nitrite Reduction”
  • NSF/ANSI 53 look for “Nitrate/Nitrite (30 ppm challenge)”

Haloacetic acids (HAA5)

Forms or is added in treatment

Below EPA’s limits

10ppb

Highest yearly average, 2020 to 2024

2024 average: 7.6 ppb

Averaged by year, the highest was 10 ppb, in 2020, below EPA’s legal limit of 60 ppb. Its highest single sample was 13 ppb. In 2024, the latest year on file, it averaged 7.6 ppb. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 10 ppb, in 2018.

What handles it

No certification claim covers this compound yet.

Chromium (total)

Comes from the source

Below EPA’s limits

8.2ppb

Highest yearly average, 2013 to 2018

2018, one sample: 5.3 ppb

Averaged by year, the highest was 8.2 ppb, in 2013, below EPA’s legal limit of 100 ppb. In 2018, the latest year on file, its one sample was 5.3 ppb.

What handles it

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.06ppm

Highest yearly average, 2013 to 2018

2018: not found

Averaged by year, the highest was 0.06 ppm, in 2015, below EPA’s legal limit of 4.0 ppm. Its highest single sample was 0.12 ppm. In 2018, the latest year on file, it wasn’t found in its one sample.

What handles it

2 compounds tested and not foundBelow the reporting level in every sample. Not found is not the same as zero.
  • Arsenic
  • 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.”

At the tap, or for the whole house?

Lead and copper usually come from pipes and fixtures inside or near your home. A whole-house system sits where water enters, so it cannot catch what your own plumbing adds after it. For those, the filter that counts is the one at the tap. 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

Compare five-year costs

Violations since 2016

No health-based violations on file with EPA since 2016. There is 1 monitoring or reporting violation: a sample missed, late or not reported.

What this report can’t tell you

  • Everything else. Uranium, total trihalomethanes (TTHM), nitrate, haloacetic acids (HAA5) and arsenic results here are New York’s own yearly summaries 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. Twin Lakes Water Co., Inc.’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; New York’s yearly summaries cover 2020 to 2024; EPA’s compliance samples are from Sept. 25, 2013 to Feb. 22, 2018.

Testing your own tap

Twin Lakes Water Co., Inc.’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 New York certifies.

The 3 labs New York certifies closest to the area Twin Lakes Water Co., Inc. serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Yorktown Medical Laboratory Inc.

    Yorktown Heights, NY · about 13 miles

    Certified for bacteria, nitrate, lead and copper

    (914) 245-3203

  • ALS Environmental - Newtown

    Newtown, CT · about 15 miles

    Certified for bacteria, nitrate, minerals and other inorganics

    (203) 540-7120

  • Westchester Co Labs and Research

    Valhalla, NY · about 17 miles

    Certified for bacteria, nitrate, lead and copper, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, PFAS

    (914) 231-1768

All 161 certified labs for New York

Sources

PWSID NY5903475. Rebuilt from EPA data on Oct. 18, 2026.

Also in Westchester County

All New York utilities

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