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Griswold MHP LLC

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
99 people
Connections
39
Water source
Groundwater
Based in
Griswold, CT
County
New London
Owner
Private
The ZIP code it serves

06351

The short answer

1 result is above EPA’s legal limit, and 2 more are above the health goal. The worst: Copper, above the action level. 1 health-based violation since 2016.

What handles it

What was found

Lead and copper: EPA SDWIS monitoring periods ending 1993 to 2026.

Uranium and nitrate: 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.

Fluoride, arsenic and chromium (total): EPA’s compliance monitoring file, samples taken from April 23, 2012 to March 18, 2019. 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

2.7ppm

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 2.7 ppm, above EPA’s action level of 1.3 ppm.

What handles it

Above the health goal2

Lead

Comes from pipes, often your own

Above the health goal

15ppb

90th percentile, 2026

In the latest period, 9 in 10 homes sampled were at or below 15 ppb, below EPA’s action level of 15 ppb. The action level drops to 10 ppb on Nov. 1, 2027, and this result is at or above that. EPA’s health goal for lead is zero.

What handles it

Uranium

Comes from the source

Above the health goal

3.3ppb

Highest yearly average, 2022

Averaged by year, the highest was 3.3 ppb, in 2022: below EPA’s legal limit of 30 ppb, but above its health goal of zero. That is the only year on file. Earlier, from 2012 to 2019, EPA’s file shows a highest yearly average of 4.4 ppb, in 2013.

What handles it

Below EPA’s limits2

Nitrate

Comes from the source

Below EPA’s limits

2.1ppm

Highest yearly average, 2020 to 2023

2023 average: 2.0 ppm

Averaged by year, the highest was 2.1 ppm, in 2021, below EPA’s legal limit of 10 ppm. In 2023, the latest year on file, it averaged 2.0 ppm. Earlier, from 2012 to 2019, EPA’s file shows a highest sample of 2.7 ppm, in 2018.

What handles it

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

Fluoride

Forms or is added in treatment

Below EPA’s limits

0.11ppm

Highest yearly average, 2012 to 2019

Averaged by year, the highest was 0.11 ppm, in 2019, below EPA’s legal limit of 4.0 ppm. That was also the latest year on file.

What handles it

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

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.”

  • NSF/ANSI 53

    Claims: Copper Reduction, Lead Reduction

    For: Copper, Lead

  • NSF/ANSI 58

    Claims: Copper Reduction, Lead Reduction, Uranium

    For: Copper, Lead, Uranium

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

The best water filters for lead, ranked

Violations since 2016

Contaminant or ruleTypePeriodMeasuredStatus
Lead and Copper RuleA required study or plan for corrosion control was not done on time.EPA: OCCT/SOWT Study/RecommendationApril 1, 2020—Resolved
Health-based violations only. Resolved and archived mean the utility returned to compliance or the state closed the record. 21 monitoring or reporting violations not shown.

What this report can’t tell you

  • Everything else. Uranium and nitrate results here are Connecticut’s yearly averages as CDC publishes them, from 2020 on, with EPA’s national file for 2012 to 2019. Fluoride, arsenic and chromium (total) come from EPA’s file alone, which ends in 2019. Griswold MHP LLC’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 23, 2012 to March 18, 2019.

Testing your own tap

Griswold MHP LLC’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 Connecticut certifies.

The 3 labs Connecticut certifies closest to the area Griswold MHP LLC serves, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.

  • Microbac Laboratories, INC. - Dayville

    Dayville, CT · about 19 miles

    Certified for bacteria, nitrate, metals, minerals and other inorganics, organic chemicals, disinfection byproducts, radioactivity

    (860) 774-6814

  • New England Testing Laboratory, Inc.

    West Warwick, RI · about 23 miles

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

    (401) 353-3420

  • Eurofins Rhode Island

    North Kingstown, RI · about 25 miles

    Certified for nitrate, metals, minerals and other inorganics

    (413) 340-3947

All 86 certified labs for Connecticut

Sources

PWSID CT0580031. Rebuilt from EPA data on Oct. 18, 2026.

Also in New London County

All Connecticut utilities

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