2026 Rankings

Worst ZIP Codes for Lead in Water in Connecticut — 2026

Last updated: June 4, 2026

335 ZIP codes ranked by Lead (mg/L) #1: ZIP 06414 (Cobalt, CT) — 14.9 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 335 ZIP codes with data in Connecticut, these are the highest-ranked areas for lead (mg/l). See also: National Worst ZIP Codes for Lead in Water | All Connecticut Rankings

Statistic Value
ZIP codes ranked 335
Highest value 14.9 ppb
Median value 2.0 ppb
State Connecticut

Top 100 Worst ZIP Codes

Rank ZIP Code City State Lead (mg/L) Safety Score
1 06414 Cobalt CT 14.9 ppb 41/100
2 06235 Chaplin CT 14.5 ppb 54/100
3 06241 Dayville CT 14.5 ppb 41/100
4 06752 Bridgewater CT 13.0 ppb 61/100
5 06477 Orange CT 12.2 ppb 42/100
6 06339 Ledyard CT 10.0 ppb 50/100
7 06481 Rockfall CT 10.0 ppb 54/100
8 06010 Bristol CT 9.0 ppb 67/100
9 06011 Bristol CT 9.0 ppb 83/100
10 06071 Somers CT 8.4 ppb 70/100
11 06281 Woodstock CT 7.9 ppb 46/100
12 06001 Avon CT 7.0 ppb 78/100
13 06032 Farmington CT 7.0 ppb 81/100
14 06033 Glastonbury CT 7.0 ppb 81/100
15 06063 Barkhamsted CT 7.0 ppb 77/100
16 06064 Poquonock CT 7.0 ppb 73/100
17 06067 Rocky Hill CT 7.0 ppb 81/100
18 06073 South Glastonbury CT 7.0 ppb 55/100
19 06074 South Windsor CT 7.0 ppb 78/100
20 06095 Windsor CT 7.0 ppb 65/100
21 06101 Hartford CT 7.0 ppb 91/100
22 06102 Hartford CT 7.0 ppb 93/100
23 06103 Hartford CT 7.0 ppb 91/100
24 06104 Hartford CT 7.0 ppb 93/100
25 06105 Hartford CT 7.0 ppb 91/100
26 06106 Hartford CT 7.0 ppb 86/100
27 06107 West Hartford CT 7.0 ppb 60/100
28 06108 East Hartford CT 7.0 ppb 65/100
29 06109 Wethersfield CT 7.0 ppb 84/100
30 06110 West Hartford CT 7.0 ppb 65/100
31 06111 Newington CT 7.0 ppb 83/100
32 06112 Hartford CT 7.0 ppb 91/100
33 06114 Hartford CT 7.0 ppb 86/100
34 06115 Hartford CT 7.0 ppb 91/100
35 06117 West Hartford CT 7.0 ppb 60/100
36 06118 East Hartford CT 7.0 ppb 60/100
37 06119 West Hartford CT 7.0 ppb 65/100
38 06120 Hartford CT 7.0 ppb 91/100
39 06123 Hartford CT 7.0 ppb 93/100
40 06126 Hartford CT 7.0 ppb 93/100
41 06132 Hartford CT 7.0 ppb 93/100
42 06134 Hartford CT 7.0 ppb 93/100
43 06140 Hartford CT 7.0 ppb 93/100
44 06141 Hartford CT 7.0 ppb 93/100
45 06142 Hartford CT 7.0 ppb 93/100
46 06143 Hartford CT 7.0 ppb 93/100
47 06144 Hartford CT 7.0 ppb 93/100
48 06145 Hartford CT 7.0 ppb 93/100
49 06146 Hartford CT 7.0 ppb 93/100
50 06147 Hartford CT 7.0 ppb 93/100
51 06150 Hartford CT 7.0 ppb 93/100
52 06151 Hartford CT 7.0 ppb 93/100
53 06152 Hartford CT 7.0 ppb 93/100
54 06153 Hartford CT 7.0 ppb 93/100
55 06154 Hartford CT 7.0 ppb 93/100
56 06155 Hartford CT 7.0 ppb 93/100
57 06156 Hartford CT 7.0 ppb 93/100
58 06160 Hartford CT 7.0 ppb 93/100
59 06161 Hartford CT 7.0 ppb 93/100
60 06167 Hartford CT 7.0 ppb 93/100
61 06176 Hartford CT 7.0 ppb 93/100
62 06180 Hartford CT 7.0 ppb 91/100
63 06183 Hartford CT 7.0 ppb 93/100
64 06199 Hartford CT 7.0 ppb 93/100
65 06259 Pomfret Center CT 5.3 ppb 78/100
66 06338 Mashantucket CT 5.3 ppb 64/100
67 06365 Preston CT 5.3 ppb 64/100
68 06013 Burlington CT 5.1 ppb 95/100
69 06016 Broad Brook CT 5.0 ppb 87/100
70 06029 Ellington CT 5.0 ppb 73/100
71 06066 Vernon Rockville CT 5.0 ppb 65/100
72 06076 Stafford Springs CT 5.0 ppb 61/100
73 06078 Suffield CT 5.0 ppb 95/100
74 06080 Suffield CT 5.0 ppb 99/100
75 06088 East Windsor CT 5.0 ppb 82/100
76 06093 West Suffield CT 5.0 ppb 66/100
77 06096 Windsor Locks CT 5.0 ppb 65/100
78 06075 Stafford CT 4.8 ppb 66/100
79 06278 Ashford CT 4.5 ppb 74/100
80 06331 Canterbury CT 4.4 ppb 66/100
81 06457 Middletown CT 4.3 ppb 56/100
82 06459 Middletown CT 4.3 ppb 61/100
83 06050 New Britain CT 4.0 ppb 99/100
84 06051 New Britain CT 4.0 ppb 95/100
85 06052 New Britain CT 4.0 ppb 85/100
86 06053 New Britain CT 4.0 ppb 90/100
87 06062 Plainville CT 4.0 ppb 82/100
88 06084 Tolland CT 4.0 ppb 70/100
89 06470 Newtown CT 4.0 ppb 57/100
90 06812 New Fairfield CT 4.0 ppb 63/100
91 06794 Washington Depot CT 3.7 ppb 81/100
92 06131 Newington CT 3.6 ppb 97/100
93 06405 Branford CT 3.3 ppb 55/100
94 06437 Guilford CT 3.3 ppb 55/100
95 06750 Bantam CT 3.0 ppb 76/100
96 06068 Salisbury CT 3.0 ppb 82/100
97 06716 Wolcott CT 3.0 ppb 61/100
98 06756 Goshen CT 3.0 ppb 69/100
99 06762 Middlebury CT 3.0 ppb 65/100
100 06850 Norwalk CT 3.0 ppb 59/100

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: 2026-06-04.

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.

Explore More Rankings

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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