2026 Rankings

ZIP Codes Ranked by Water-System Lead Results…

Last updated: October 14, 2026

81 ZIP codes ranked by Lead (ppb) #1: ZIP 06238 (Coventry, CT) - 9.2 ppb
Lead Violations Lowest Score Safest Flood Risk Energy Cost Radon PFAS Reliability EJ Index Homebuyer Risk CO & Gas Safest Gas Remediation Burden Unresolved Violations (by Utility) Water Equity (by Utility)

Out of 81 ZIP codes with data in Connecticut, these are the highest-ranked areas for lead (ppb). See also: National Worst ZIP Codes for Lead in Water | All Connecticut Rankings

Statistic Value
ZIP codes ranked 81
Highest value 9.2 ppb
Median value 1.9 ppb
State Connecticut

Top 81 Worst ZIP Codes

Rank ZIP Code City State Lead (ppb) Safety Score
1 06238 Coventry CT 9.2 ppb 77/100
2 06370 Oakdale CT 7.6 ppb —
3 06804 Brookfield CT 6.1 ppb 33/100
4 06365 Preston CT 5.3 ppb 47/100
5 06482 Sandy Hook CT 4.0 ppb 33/100
6 06777 New Preston Marble Dale CT 3.7 ppb —
7 06793 Washington CT 3.7 ppb —
8 06794 Washington Depot CT 3.7 ppb 67/100
9 06335 Gales Ferry CT 3.3 ppb —
10 06339 Ledyard CT 3.3 ppb —
11 06877 Ridgefield CT 3.1 ppb 42/100
12 06037 Berlin CT 2.8 ppb 67/100
13 06787 Thomaston CT 2.8 ppb 83/100
14 06812 New Fairfield CT 2.8 ppb —
15 06001 Avon CT 2.4 ppb 83/100
16 06032 Farmington CT 2.4 ppb 81/100
17 06085 Unionville CT 2.4 ppb 83/100
18 06089 Weatogue CT 2.4 ppb 72/100
19 06374 Plainfield CT 2.3 ppb —
20 06795 Watertown CT 2.2 ppb 76/100
21 06031 Falls Village CT 2.0 ppb —
22 06424 East Hampton CT 2.0 ppb —
23 06755 Gaylordsville CT 2.0 ppb 67/100
24 06757 Kent CT 2.0 ppb —
25 06776 New Milford CT 2.0 ppb 50/100
26 06779 Oakville CT 2.0 ppb 78/100
27 06785 South Kent CT 2.0 ppb —
28 06016 Broad Brook CT 1.9 ppb 83/100
29 06029 Ellington CT 1.9 ppb 66/100
30 06066 Vernon Rockville CT 1.9 ppb 64/100
31 06071 Somers CT 1.9 ppb 65/100
32 06074 South Windsor CT 1.9 ppb 80/100
33 06076 Stafford Springs CT 1.9 ppb —
34 06078 Suffield CT 1.9 ppb 83/100
35 06080 Suffield CT 1.9 ppb —
36 06082 Enfield CT 1.9 ppb 81/100
37 06084 Tolland CT 1.9 ppb 63/100
38 06088 East Windsor CT 1.9 ppb 83/100
39 06093 West Suffield CT 1.9 ppb 83/100
40 06096 Windsor Locks CT 1.9 ppb 83/100
41 06359 North Stonington CT 1.9 ppb —
42 06231 Amston CT 1.5 ppb —
43 06248 Hebron CT 1.5 ppb —
44 06375 Quaker Hill CT 1.5 ppb —
45 06385 Waterford CT 1.5 ppb 64/100
46 06420 Salem CT 1.5 ppb —
47 06801 Bethel CT 1.4 ppb 36/100
48 06018 Canaan CT 1.3 ppb —
49 06024 East Canaan CT 1.3 ppb —
50 06057 New Hartford CT 1.3 ppb 82/100
51 06255 North Grosvenordale CT 1.1 ppb —
52 06262 Quinebaug CT 1.1 ppb —
53 06277 Thompson CT 1.1 ppb 67/100
54 06403 Beacon Falls CT 1.1 ppb 50/100
55 06478 Oxford CT 1.1 ppb 50/100
56 06483 Seymour CT 1.1 ppb 50/100
57 06784 Sherman CT 1.0 ppb —
58 06798 Woodbury CT 1.0 ppb 83/100
59 06250 Mansfield Center CT 0.7 ppb 73/100
60 06268 Storrs Mansfield CT 0.7 ppb 50/100
61 06269 Storrs Mansfield CT 0.7 ppb 59/100
62 06488 Southbury CT 0.7 ppb 33/100
63 06762 Middlebury CT 0.7 ppb 48/100
64 06069 Sharon CT 0.6 ppb —
65 06782 Plymouth CT 0.6 ppb —
66 06786 Terryville CT 0.6 ppb 83/100
67 06234 Brooklyn CT 0.5 ppb 67/100
68 06239 Danielson CT 0.5 ppb 67/100
69 06241 Dayville CT 0.5 ppb 67/100
70 06263 Rogers CT 0.5 ppb 67/100
71 06026 East Granby CT 0.3 ppb 67/100
72 06035 Granby CT 0.3 ppb 81/100
73 06070 Simsbury CT 0.3 ppb 69/100
74 06081 Tariffville CT 0.3 ppb —
75 06092 West Simsbury CT 0.3 ppb 83/100
76 06702 Waterbury CT 0.0 ppb 65/100
77 06704 Waterbury CT 0.0 ppb 63/100
78 06705 Waterbury CT 0.0 ppb 65/100
79 06706 Waterbury CT 0.0 ppb 65/100
80 06708 Waterbury CT 0.0 ppb 63/100
81 06710 Waterbury CT 0.0 ppb —

Methodology

Lead rankings are based on the 90th percentile lead testing value (PB90) reported by water systems under the Lead and Copper Rule. When CCR data is unavailable, EPA SDWIS lead sampling data is used. The EPA action level for lead is 15 ppb (0.015 mg/L). There is no safe level of lead exposure.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-10-14.

Frequently Asked Questions

What is a dangerous lead level in water?

The EPA action level is 15 parts per billion (ppb). The American Academy of Pediatrics recommends no more than 1 ppb for school drinking water. There is no safe level of lead exposure for children.

How is lead measured in water?

Water systems collect samples from homes with known lead service lines or lead solder. The 90th percentile value (PB90) means 90% of samples tested below that level. If PB90 exceeds 15 ppb, the system must take corrective action.

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How this ranking is calculated, data sources, and limitations: Rankings Methodology →

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Disclaimer: Rankings are based on EPA, FEMA, and federal agency data. They reflect historical patterns and risk indicators, not necessarily current conditions. For the most current information, contact your local water utility or request a Consumer Confidence Report.

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