EPA data as of Oct 2026 · page updated 2026-10-29

Home hazard report for 06338 — Mashantucket, CT

ZIP 06338 is served by Mashantucket Pequot Water System (as listed by the state): 2 violations since 2016, latest lead result 1 ppb, PFAS 7.4 ppt. New London County is in EPA radon zone 1.

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Where ZIP 06338 is

Dashed: ZIP area · blue: utility service area · scroll or pinch to zoom
ZIP code areaZIP center Water utility service area PFOA/PFOS ≥ 4 ppt Lead > 15 ppb 5+ violations Superfund site (active) proposed cleaned up Circles: other water systems flagged nearby; size = people served. Tap any symbol for details.

Drinking water: Mashantucket Pequot Water System

EPA ID010106001
People served22,171
Sourcesurface water (rivers, lakes)
Connections119

Health-based violations

Contaminant or ruleHealth-based violations since 2016
Tthm2

A health-based violation means a contaminant exceeded its legal limit (MCL) or a required treatment technique was not met, as reported by the state to EPA’s SDWIS. All are listed as resolved or archived; the latest began Oct 2018.

Full record for Mashantucket Pequot Water System →

Lead

Jan 20231 ppb
Jan 20203.9 ppb
Jan 20172.3 ppb
Jan 20144 ppb
Jan 20111 ppb
Jan 20101 ppb
Jul 20071 ppb
Jul 20044 ppb

90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.

PFAS (“forever chemicals”)

CompoundHighest resultSamples with detectionEPA limit
PFPeA19.1 ppt4 of 4—
PFHxA9.9 ppt3 of 4—
PFOA7.4 ppt3 of 44 ppt MCL
PFBA6.5 ppt3 of 4—
PFHpA3.6 ppt3 of 4—
PFBS3.6 ppt3 of 4—
PFHxSnot detected0 of 4—
PFNAnot detected0 of 4—
PFOSnot detected0 of 44 ppt MCL
PFDAnot detected0 of 4—
HFPO-DA (GenX)not detected0 of 4—

EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), samples 2023–2025; ppt = parts per trillion (ng/L). The 4.0 ppt maximum contaminant levels for PFOA and PFOS were set by EPA in 2024; water systems have until the end of the decade to comply.

Radon in New London County

EPA radon zone 1 — highest potential. Predicted average indoor radon above 4 pCi/L — EPA’s action level. Test your home.

Radon is a colorless, odorless radioactive gas from soil and rock, and the leading cause of lung cancer among non-smokers. EPA recommends fixing a home at 4 pCi/L or above and considering it from 2 pCi/L. A short-term test kit costs about $15–30. How radon zones work →

Superfund sites nearby

SiteStatusDistance
New London Submarine Base
New London, Connecticut · EPA ID CTD980906515
Active (final NPL)7.4 mi

EPA Superfund National Priorities List (NPL): the country’s most serious known hazardous-waste sites, each with an EPA cleanup record (linked). Distance is measured from the ZIP center to the site’s reference point; being near a site does not by itself mean exposure — EPA site pages describe what was found and how it is being cleaned up.

What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.

Questions about 06338

Who supplies drinking water to ZIP 06338?

Mashantucket Pequot Water System (EPA ID 010106001), a surface water (rivers, lakes) system serving about 22,171 people, listed by the state as serving this ZIP code.

Is there lead in Mashantucket, CT tap water?

The utility’s latest 90th-percentile lead result (Jan 2023) was 1 ppb; EPA’s action level is 15 ppb, falling to 10 ppb from 2027. Lead mostly comes from service lines and home plumbing, so the only way to know your tap is to test it.

Does Mashantucket, CT water have PFAS?

Highest PFOA or PFOS result in EPA’s 2023–2025 testing was at or above 4.0 ppt, EPA’s 2024 maximum contaminant level for each. 6 PFAS compounds detected.

Has the water system in 06338 had violations?

Health-based violations since 2016: Tthm. All are listed as resolved.

Are there Superfund sites near 06338?

The nearest active Superfund site is 7.4 miles away. Sites within 10 miles: New London Submarine Base (7.4 mi, Active (final NPL)).

Is radon a problem in New London County?

New London County is in EPA radon zone 1 (highest potential). Predicted average indoor radon above 4 pCi/L — EPA’s action level. Test your home.