New London County, Connecticut
38 ZIP codes · Avg score 50/100 · Grade D · Updated
ZipCheckup grade for New London County: D.
Several federal signals point to home-safety risks in this ZIP.
Drinking water quality in New London County has lagged behind state benchmarks - multiple documented violations across 38 ZIP codes keep the county's grade low.
How New London County Compares
How New London County Compares
New London County scores 13 points below the Connecticut state average (63/100) and 23 points below the national average (73/100).
Data: ZipCheckup Home Safety Score model 4.0.0; EPA SDWIS, UCMR 5, EPA radon zones, EPA AirData Last verified:
ZIP Code Risk Map
Water Quality Map: New London County, Connecticut
Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.
Key Risk Factors
Estimated additional annual cost per homeowner: $2,188, driven primarily by flood
69.4% of homes built before 1978 (lead paint era)
Violation History (2021–2025)
↑ Worsening trendEPA violation counts by year across New London County water systems. Health-based shown in red, total in blue.
Peak year: 2024 with 18 violations. Past 5 years: 36 total (36 health-based). Health-based violations are rising versus the prior 2-year window - worth closer monitoring.
Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.
Infrastructure Overview
Modeled area-level indicator, not a failure probability. Sources: Census ACS housing age, EPA DWINS infrastructure needs, EPA SDWIS violations, and EPA lead indicators.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $2,188
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
123,123 housing units in New London County
Source: U.S. Census Bureau ACS B25034 (Year Structure Built).
Water Safety Affordability
How much it costs to fix water issues relative to home values in New London County
Remediation costs are relatively manageable for most homeowners in New London County, representing a small fraction of property value.
Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.
Water systems serving New London County
8 community water systems serving New London County.
- D
- C
- C
- C
- F
- D
Show all 8 water systems
- D
- D
37 total water systems serve New London County.
Systems with the most violations in New London County
5 water systems with recorded EPA violations.
- F
- D
- C
- C
- D
All ZIP Codes in New London County
38 ZIP codes tracked in New London County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 06378 | Stonington | 66 | C | 1 | $576K |
| 2 | 06320 | New London | 64 | C | 7 | $235K |
| 3 | 06355 | Mystic | 64 | C | 7 | $417K |
| 4 | 06385 | Waterford | 64 | C | 9 | $335K |
| 5 | 06340 | Groton | 55 | C | 26 (1 health) | $276K |
| 6 | 06334 | Bozrah | 50 | D | 0 | $294K |
| 7 | 06360 | Norwich | 50 | D | 1 | $234K |
| 8 | 06379 | Pawcatuck | 50 | D | 0 | $365K |
| 9 | 06380 | Taftville | 50 | D | 1 | $187K |
| 10 | 06389 | Yantic | 50 | D | 0 | — |
| 11 | 06338 | Mashantucket | 47 | D | 5 (3 health) | — |
| 12 | 06365 | Preston | 47 | D | 7 (1 health) | $343K |
| 13 | 06351 | Jewett City | 46 | D | 9 (1 health) | $276K |
| 14 | 06382 | Uncasville | 41 | D | 14 (4 health) | $250K |
| 15 | 06415 | Colchester | 41 | D | 17 (2 health) | $341K |
| 16 | 06333 | East Lyme | 36 | F | 42 | $433K |
| 17 | 06357 | Niantic | 36 | F | 42 | $370K |
| 18 | 06249 | Lebanon | — | — | $338K | |
| 19 | 06254 | North Franklin | — | — | $288K | |
| 20 | 06330 | Baltic | — | — | 5 | $266K |
| 21 | 06335 | Gales Ferry | — | — | 5 (1 health) | $297K |
| 22 | 06336 | Gilman | — | — | $425K | |
| 23 | 06339 | Ledyard | — | — | 9 (4 health) | $284K |
| 24 | 06349 | Groton | — | — | — | |
| 25 | 06350 | Hanover | — | — | $238K | |
| 26 | 06353 | Montville | — | — | — | |
| 27 | 06359 | North Stonington | — | — | 1 | $375K |
| 28 | 06370 | Oakdale | — | — | 46 (1 health) | $305K |
| 29 | 06371 | Old Lyme | — | — | 3 (1 health) | $468K |
| 30 | 06372 | Old Mystic | — | — | — | |
| 31 | 06375 | Quaker Hill | — | — | 4 | $295K |
| 32 | 06376 | South Lyme | — | — | $888K | |
| 33 | 06383 | Versailles | — | — | — | |
| 34 | 06384 | Voluntown | — | — | $334K | |
| 35 | 06388 | West Mystic | — | — | — | |
| 36 | 06420 | Salem | — | — | 0 | $370K |
| 37 | 06439 | Hadlyme | — | — | $589K | |
| 38 | 06474 | North Westchester | — | — | — |
Recommended Buyer Guides for New London County
Editorial methodology pairs each documented risk in this county with the buyer category that addresses it, drawing on water-quality detections, housing-stock lead exposure, EPA Radon Zone designation, and FEMA flood and wildfire ratings. NSF-certified options surface where applicable, and products that match the specific contaminant take priority.
- Best Water Filters for PFAS — PFAS detected in 3 ZIP codes
- Best Lead Paint Test Kits — 69.4% of homes built before 1978
- Best Under-Sink Reverse Osmosis Systems — Multi-contaminant removal at the kitchen tap
- Best Radon Test Kits — EPA Radon Zone 1 (highest risk) dominant in county
- Best Sump Pumps — Flood is the top compound risk factor
Deep Dive Reports
Detailed analysis for New London County, Connecticut
Overview
New London County in Connecticut covers 38 tracked ZIP records with an average Home Safety Score of D (50/100) across 17 scored records.
21 of 25 ZIP codes with a reported violation count in the available EPA record have recorded EPA violations. 15 health-based violations appear in the available health breakdown.
← Back to Connecticut Home Safety Profile
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- PFAS screening: EPA UCMR 5
- Radon zones: EPA Map of Radon Zones
- Air quality: EPA AirData annual AQI
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Reporting periods vary by source. Missing data is shown as unavailable, not as zero.
What You Can Do
New London County has a grade of D. Here are steps to protect your household.
Test your tap water
Order a certified lab test kit ($20-$50) to check for lead, bacteria, and other contaminants specific to your ZIP code.
Consider a certified water filter
NSF-certified filters can remove most common contaminants. Match the filter to your test results for best protection. Try our filter matcher
Contact your water utility
Request the latest Consumer Confidence Report (CCR) from your water provider. It details exactly what was found in your water supply.
Check for lead in your home
69.4% of homes in this county were built before 1978. Older plumbing and solder can leach lead into drinking water, especially in the morning.