2026 Rankings

Least Reliable Water Systems in Connecticut — 2026

Last updated: April 13, 2026

433 ZIP codes ranked by Reliability Score #1: ZIP 06241 (Dayville, CT) - 10/100
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 433 ZIP codes with data in Connecticut, these are the lowest-ranked areas for reliability score. See also: National Least Reliable Water Systems in America | All Connecticut Rankings

Statistic Value
ZIP codes ranked 433
Lowest value 10/100
Median value 75/100
State Connecticut

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Reliability Score Safety Score
1 06241 Dayville CT 10/100 41/100
2 06258 Pomfret CT 10/100 50/100
3 06279 Willington CT 10/100 66/100
4 06331 Canterbury CT 10/100 66/100
5 06281 Woodstock CT 15/100 46/100
6 06088 East Windsor CT 19/100 82/100
7 06002 Bloomfield CT 20/100 69/100
8 06043 Bolton CT 20/100 67/100
9 06108 East Hartford CT 20/100 65/100
10 06118 East Hartford CT 20/100 60/100
11 06128 East Hartford CT 20/100 66/100
12 06138 East Hartford CT 20/100 66/100
13 06234 Brooklyn CT 20/100 68/100
14 06260 Putnam CT 21/100 71/100
15 06074 South Windsor CT 22/100 78/100
16 06084 Tolland CT 25/100 70/100
17 06371 Old Lyme CT 25/100 40/100
18 06026 East Granby CT 26/100 83/100
19 06278 Ashford CT 26/100 74/100
20 06353 Montville CT 28/100 60/100
21 06422 Durham CT 28/100 60/100
22 06420 Salem CT 29/100 62/100
23 06232 Andover CT 31/100 74/100
24 06776 New Milford CT 31/100 67/100
25 06763 Morris CT 32/100 74/100
26 06016 Broad Brook CT 34/100 87/100
27 06249 Lebanon CT 34/100 62/100
28 06357 Niantic CT 34/100 52/100
29 06426 Essex CT 34/100 52/100
30 06470 Newtown CT 34/100 57/100
31 06471 North Branford CT 34/100 55/100
32 06756 Goshen CT 35/100 69/100
33 06335 Gales Ferry CT 36/100 56/100
34 06790 Torrington CT 36/100 72/100
35 06792 Torrington CT 36/100 76/100
36 06370 Oakdale CT 37/100 66/100
37 06408 Cheshire CT 37/100 50/100
38 06410 Cheshire CT 37/100 48/100
39 06411 Cheshire CT 37/100 50/100
40 06415 Colchester CT 37/100 66/100
41 06417 Deep River CT 37/100 61/100
42 06516 West Haven CT 37/100 51/100
43 06757 Kent CT 37/100 74/100
44 06033 Glastonbury CT 39/100 81/100
45 06001 Avon CT 42/100 78/100
46 06037 Berlin CT 42/100 81/100
47 06067 Rocky Hill CT 42/100 81/100
48 06082 Enfield CT 42/100 81/100
49 06083 Enfield CT 42/100 94/100
50 06712 Prospect CT 42/100 66/100
51 06795 Watertown CT 42/100 74/100
52 06235 Chaplin CT 44/100 54/100
53 06277 Thompson CT 44/100 74/100
54 06351 Jewett City CT 44/100 60/100
55 06365 Preston CT 44/100 64/100
56 06374 Plainfield CT 44/100 74/100
57 06419 Killingworth CT 44/100 65/100
58 06030 Farmington CT 45/100 91/100
59 06032 Farmington CT 45/100 81/100
60 06034 Farmington CT 45/100 94/100
61 06075 Stafford CT 45/100 66/100
62 06076 Stafford Springs CT 45/100 61/100
63 06226 Willimantic CT 45/100 74/100
64 06360 Norwich CT 46/100 49/100
65 06069 Sharon CT 47/100 74/100
66 06259 Pomfret Center CT 47/100 78/100
67 06414 Cobalt CT 47/100 41/100
68 06424 East Hampton CT 47/100 61/100
69 06450 Meriden CT 47/100 56/100
70 06451 Meriden CT 47/100 56/100
71 06454 Meriden CT 47/100 61/100
72 06455 Middlefield CT 47/100 66/100
73 06481 Rockfall CT 47/100 54/100
74 06785 South Kent CT 47/100 78/100
75 06798 Woodbury CT 47/100 74/100
76 06801 Bethel CT 47/100 59/100
77 06824 Fairfield CT 47/100 46/100
78 06825 Fairfield CT 47/100 51/100
79 06828 Fairfield CT 47/100 61/100
80 06070 Simsbury CT 49/100 80/100
81 06412 Chester CT 49/100 54/100
82 06492 Wallingford CT 49/100 55/100
83 06493 Wallingford CT 49/100 60/100
84 06494 Wallingford CT 49/100 60/100
85 06495 Wallingford CT 49/100 60/100
86 06447 Marlborough CT 50/100 91/100
87 06482 Sandy Hook CT 50/100 51/100
88 06488 Southbury CT 50/100 51/100
89 06262 Quinebaug CT 52/100 78/100
90 06457 Middletown CT 52/100 56/100
91 06459 Middletown CT 52/100 61/100
92 06480 Portland CT 52/100 56/100
93 06901 Stamford CT 52/100 69/100
94 06902 Stamford CT 52/100 54/100
95 06903 Stamford CT 52/100 59/100
96 06904 Stamford CT 52/100 69/100
97 06905 Stamford CT 52/100 59/100
98 06906 Stamford CT 52/100 64/100
99 06907 Stamford CT 52/100 64/100
100 06910 Stamford CT 52/100 65/100

Methodology

Water system reliability scores (0-100) combine violation frequency, violation recency, resolution rate, and system size. Systems with repeated health-based violations and unresolved issues score lowest. The reliability score focuses specifically on the water utility performance, distinct from the broader Home Safety Score.

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: 2026-04-13.

Frequently Asked Questions

What does a low water reliability score mean?

A low reliability score (below 50) indicates a water system with frequent violations, poor resolution rates, or recurring compliance issues. These systems may have aging infrastructure, inadequate treatment, or management challenges.

How is reliability different from safety score?

The reliability score focuses specifically on the water utility performance (violations, resolution, compliance). The Home Safety Score is broader, also including lead risk, radon, and flood data. A ZIP code can have a reliable water system but still have high radon or flood risk.

Explore More Rankings

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

Related Rankings

Home Safety 2026 Water compliance, PFAS, radon, and annual AQI score inputs PFAS 2026 Forever chemicals detected in drinking water Lead Risk 2026 Lead pipe infrastructure and EPA exceedances
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.

Get safety alerts for Connecticut

Free updates when EPA data changes for this area. No spam.

Unsubscribe anytime. Privacy Policy.

Share This Page

X Facebook
Check your water filter options Free tool - no phone call required.