2026 Rankings

Least Reliable Water Systems in New Hampshire — 2026

Last updated: April 13, 2026

282 ZIP codes ranked by Reliability Score #1: ZIP 03307 (Loudon, NH) - 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 282 ZIP codes with data in New Hampshire, these are the lowest-ranked areas for reliability score. See also: National Least Reliable Water Systems in America | All New Hampshire Rankings

Statistic Value
ZIP codes ranked 282
Lowest value 10/100
Median value 75/100
State New Hampshire

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Reliability Score Safety Score
1 03307 Loudon NH 10/100 40/100
2 03574 Bethlehem NH 23/100 52/100
3 03216 Andover NH 25/100 51/100
4 03256 New Hampton NH 25/100 33/100
5 03281 Weare NH 25/100 57/100
6 03301 Concord NH 25/100 53/100
7 03302 Concord NH 25/100 58/100
8 03303 Concord NH 25/100 53/100
9 03305 Concord NH 25/100 50/100
10 03838 Glen NH 25/100 15/100
11 03885 Stratham NH 25/100 55/100
12 03042 Epping NH 30/100 50/100
13 03849 Madison NH 30/100 12/100
14 03811 Atkinson NH 35/100 66/100
15 03865 Plaistow NH 38/100 65/100
16 03869 Rollinsford NH 39/100 40/100
17 03047 Greenfield NH 40/100 53/100
18 03812 Bartlett NH 40/100 60/100
19 03076 Pelham NH 45/100 62/100
20 03819 Danville NH 49/100 70/100
21 03826 East Hampstead NH 49/100 70/100
22 03855 New Durham NH 49/100 73/100
23 03741 Canaan NH 52/100 52/100
24 03825 Barrington NH 53/100 73/100
25 03748 Enfield NH 54/100 70/100
26 03234 Epsom NH 55/100 65/100
27 03242 Henniker NH 55/100 54/100
28 03608 Walpole NH 55/100 69/100
29 03229 Contoocook NH 56/100 72/100
30 03823 Madbury NH 56/100 46/100
31 03079 Salem NH 57/100 69/100
32 03470 Winchester NH 57/100 69/100
33 03756 Lebanon NH 57/100 78/100
34 03766 Lebanon NH 57/100 74/100
35 03872 Sanbornville NH 57/100 50/100
36 03254 Moultonborough NH 58/100 41/100
37 03049 Hollis NH 59/100 73/100
38 03817 Chocorua NH 59/100 53/100
39 03886 Tamworth NH 59/100 43/100
40 03285 Thornton NH 60/100 53/100
41 03861 Lee NH 60/100 71/100
42 03045 Goffstown NH 61/100 62/100
43 03077 Raymond NH 61/100 70/100
44 03253 Meredith NH 61/100 78/100
45 03304 Bow NH 61/100 71/100
46 03846 Jackson NH 61/100 59/100
47 03238 Glencliff NH 62/100 49/100
48 03266 Rumney NH 62/100 49/100
49 03275 Suncook NH 62/100 64/100
50 03279 Warren NH 62/100 74/100
51 03249 Gilford NH 64/100 73/100
52 03839 Rochester NH 64/100 81/100
53 03866 Rochester NH 64/100 81/100
54 03867 Rochester NH 64/100 76/100
55 03868 Rochester NH 64/100 81/100
56 03882 Effingham NH 64/100 51/100
57 03031 Amherst NH 65/100 65/100
58 03087 Windham NH 65/100 75/100
59 03255 Newbury NH 65/100 57/100
60 03269 Sanbornton NH 65/100 75/100
61 03290 Nottingham NH 65/100 70/100
62 03442 Bennington NH 65/100 70/100
63 03579 Errol NH 65/100 75/100
64 03878 Somersworth NH 65/100 71/100
65 03743 Claremont NH 67/100 77/100
66 03801 Portsmouth NH 67/100 77/100
67 03802 Portsmouth NH 67/100 82/100
68 03803 Portsmouth NH 67/100 82/100
69 03804 Portsmouth NH 67/100 82/100
70 03816 Center Tuftonboro NH 67/100 31/100
71 03818 Conway NH 67/100 59/100
72 03845 Intervale NH 67/100 69/100
73 03848 Kingston NH 67/100 56/100
74 03894 Wolfeboro NH 67/100 69/100
75 03057 Mont Vernon NH 68/100 50/100
76 03261 Northwood NH 68/100 73/100
77 03447 Fitzwilliam NH 68/100 58/100
78 03461 Rindge NH 68/100 58/100
79 03771 Monroe NH 68/100 78/100
80 03809 Alton NH 69/100 55/100
81 03048 Greenville NH 70/100 55/100
82 03055 Milford NH 70/100 82/100
83 03244 Hillsborough NH 70/100 69/100
84 03245 Holderness NH 70/100 47/100
85 03452 Jaffrey NH 70/100 71/100
86 03458 Peterborough NH 70/100 67/100
87 03580 Franconia NH 70/100 56/100
88 03753 Grantham NH 70/100 76/100
89 03765 Haverhill NH 70/100 73/100
90 03770 Meriden NH 70/100 72/100
91 03774 North Haverhill NH 70/100 71/100
92 03814 Center Ossipee NH 70/100 34/100
93 03836 Freedom NH 70/100 61/100
94 03854 New Castle NH 70/100 70/100
95 03860 North Conway NH 70/100 63/100
96 03864 Ossipee NH 70/100 38/100
97 03874 Seabrook NH 70/100 70/100
98 03034 Candia NH 73/100 74/100
99 03036 Chester NH 73/100 75/100
100 03071 New Ipswich NH 73/100 74/100

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.

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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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