New London County, Connecticut
34 ZIP codes · Avg score 55/100 · Grade C · Updated 2026-07-19
ZipCheckup grade for New London: C.
A mixed picture - some signals here are worth your attention.
Compared to top-scoring counties, New London County's 34 ZIP codes land in the middle tier - some meet standards cleanly, others carry documented violations, and the gap between the best and worst areas is wider than average.
How New London County Compares
How New London County Compares
New London County scores 10 points below the Connecticut state average (65/100) and 13 points below the national average (68/100).
Data: EPA SDWIS Last verified: 2026-07-19
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: $2,177, driven primarily by flood
Infrastructure: 0.444% avg pipe failure probability, 79% of ZIPs at high risk
67% 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 23 violations. Past 5 years: 42 total (42 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
Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.
Compound Risk Breakdown
Estimated additional annual cost per homeowner: $2,177
Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).
Housing Age Distribution
120,535 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.
- C
- D
- C
- C
- D
- C
Show all 8 water systems
- D
- D
62 total water systems serve New London County.
Systems with the most violations in New London County
5 water systems with recorded EPA violations.
- D
- D
- D
- C
- D
All ZIP Codes in New London County
34 ZIP codes tracked in New London County.
| # | ZIP Code | City | Safety Score | Grade | Violations | Home Value |
|---|---|---|---|---|---|---|
| 1 | 06388 | West Mystic | 70 | B | 0 | — |
| 2 | 06384 | Voluntown | 69 | C | 2 (1 health) | $334K |
| 3 | 06382 | Uncasville | 68 | C | 5 (2 health) | $250K |
| 4 | 06370 | Oakdale | 66 | C | 9 (1 health) | $305K |
| 5 | 06415 | Colchester | 66 | C | 25 (1 health) | $341K |
| 6 | 06338 | Mashantucket | 64 | C | 7 (1 health) | — |
| 7 | 06365 | Preston | 64 | C | 10 (2 health) | $343K |
| 8 | 06375 | Quaker Hill | 64 | C | 2 | $295K |
| 9 | 06330 | Baltic | 63 | C | 5 | $266K |
| 10 | 06249 | Lebanon | 62 | C | 8 (2 health) | $338K |
| 11 | 06359 | North Stonington | 62 | C | 4 | $375K |
| 12 | 06420 | Salem | 62 | C | 19 (2 health) | $370K |
| 13 | 06351 | Jewett City | 60 | C | 13 (2 health) | $276K |
| 14 | 06353 | Montville | 60 | C | 18 (4 health) | — |
| 15 | 06378 | Stonington | 60 | C | 1 | $576K |
| 16 | 06333 | East Lyme | 59 | C | 2 | $433K |
| 17 | 06335 | Gales Ferry | 56 | C | 12 (3 health) | $297K |
| 18 | 06385 | Waterford | 56 | C | 9 | $335K |
| 19 | 06349 | Groton | 54 | D | 18 | — |
| 20 | 06376 | South Lyme | 53 | D | 0 | $888K |
| 21 | 06383 | Versailles | 53 | D | 0 | — |
| 22 | 06357 | Niantic | 52 | D | 20 (2 health) | $370K |
| 23 | 06355 | Mystic | 51 | D | 6 | $417K |
| 24 | 06339 | Ledyard | 50 | D | 8 (3 health) | $284K |
| 25 | 06360 | Norwich | 49 | D | 7 (3 health) | $234K |
| 26 | 06254 | North Franklin | 45 | D | 0 | $288K |
| 27 | 06372 | Old Mystic | 45 | D | 0 | — |
| 28 | 06379 | Pawcatuck | 45 | D | 0 | $365K |
| 29 | 06340 | Groton | 43 | D | 18 | $276K |
| 30 | 06320 | New London | 40 | D | 0 | $235K |
| 31 | 06336 | Gilman | 40 | D | 0 | $425K |
| 32 | 06350 | Hanover | 40 | D | 0 | $238K |
| 33 | 06371 | Old Lyme | 40 | D | 27 (6 health) | $468K |
| 34 | 06474 | North Westchester | 40 | D | 0 | — |
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 Lead Paint Test Kits — 67% 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
- Best Mold Test Kits — Flood-driven moisture and mold risk
Deep Dive Reports
Detailed analysis for New London County, Connecticut
Overview
New London County in Connecticut covers 34 ZIP codes with an average Home Safety Score of C (55/100).
24 of 34 ZIP codes have recorded EPA violations. 35 health-based violations have been documented.
← Back to Connecticut water quality report
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Home values: U.S. Census Bureau ACS (median estimates by ZCTA)
Updated daily.