2026 Rankings

Least Reliable Water Systems in District of Columbia...

Last updated: June 4, 2026

286 ZIP codes ranked by Reliability Score #1: ZIP 20001 (Washington, DC) — 40/100
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 286 ZIP codes with data in District of Columbia, these are the lowest-ranked areas for reliability score. See also: National Least Reliable Water Systems in America | All District of Columbia Rankings

Statistic Value
ZIP codes ranked 286
Lowest value 40/100
Median value 40/100
State District of Columbia

100 Lowest-Ranked ZIP Codes

Rank ZIP Code City State Reliability Score Safety Score
1 20001 Washington DC 40/100 67/100
2 20002 Washington DC 40/100 67/100
3 20003 Washington DC 40/100 72/100
4 20004 Washington DC 40/100 72/100
5 20005 Washington DC 40/100 72/100
6 20006 Washington DC 40/100 72/100
7 20007 Washington DC 40/100 62/100
8 20008 Washington DC 40/100 67/100
9 20009 Washington DC 40/100 67/100
10 20010 Washington DC 40/100 67/100
11 20011 Washington DC 40/100 67/100
12 20012 Washington DC 40/100 67/100
13 20013 Washington DC 40/100 69/100
14 20015 Washington DC 40/100 67/100
15 20016 Washington DC 40/100 67/100
16 20017 Washington DC 40/100 67/100
17 20018 Washington DC 40/100 67/100
18 20019 Washington DC 40/100 62/100
19 20020 Washington DC 40/100 67/100
20 20022 Washington DC 40/100 69/100
21 20023 Washington DC 40/100 69/100
22 20024 Washington DC 40/100 72/100
23 20026 Washington DC 40/100 69/100
24 20027 Washington DC 40/100 72/100
25 20029 Washington DC 40/100 69/100
26 20030 Washington DC 40/100 69/100
27 20032 Washington DC 40/100 72/100
28 20033 Washington DC 40/100 69/100
29 20035 Washington DC 40/100 69/100
30 20036 Washington DC 40/100 72/100
31 20037 Washington DC 40/100 72/100
32 20038 Washington DC 40/100 69/100
33 20039 Washington DC 40/100 69/100
34 20040 Washington DC 40/100 69/100
35 20041 Washington DC 40/100 69/100
36 20042 Washington DC 40/100 69/100
37 20043 Washington DC 40/100 69/100
38 20044 Washington DC 40/100 69/100
39 20045 Washington DC 40/100 69/100
40 20046 Washington DC 40/100 69/100
41 20047 Washington DC 40/100 69/100
42 20049 Washington DC 40/100 69/100
43 20050 Washington DC 40/100 69/100
44 20051 Washington DC 40/100 69/100
45 20052 Washington DC 40/100 69/100
46 20053 Washington DC 40/100 69/100
47 20055 Washington DC 40/100 69/100
48 20056 Washington DC 40/100 69/100
49 20057 Washington DC 40/100 69/100
50 20058 Washington DC 40/100 69/100
51 20059 Washington DC 40/100 69/100
52 20060 Washington DC 40/100 69/100
53 20061 Washington DC 40/100 69/100
54 20062 Washington DC 40/100 69/100
55 20063 Washington DC 40/100 69/100
56 20064 Washington DC 40/100 69/100
57 20065 Washington DC 40/100 69/100
58 20066 Washington DC 40/100 69/100
59 20067 Washington DC 40/100 69/100
60 20068 Washington DC 40/100 69/100
61 20069 Washington DC 40/100 69/100
62 20070 Washington DC 40/100 69/100
63 20071 Washington DC 40/100 69/100
64 20073 Washington DC 40/100 69/100
65 20074 Washington DC 40/100 69/100
66 20075 Washington DC 40/100 69/100
67 20076 Washington DC 40/100 69/100
68 20077 Washington DC 40/100 69/100
69 20078 Washington DC 40/100 69/100
70 20080 Washington DC 40/100 69/100
71 20081 Washington DC 40/100 69/100
72 20082 Washington DC 40/100 69/100
73 20088 Washington DC 40/100 69/100
74 20090 Washington DC 40/100 69/100
75 20091 Washington DC 40/100 69/100
76 20097 Washington DC 40/100 69/100
77 20098 Washington DC 40/100 69/100
78 20201 Washington DC 40/100 69/100
79 20202 Washington DC 40/100 69/100
80 20203 Washington DC 40/100 69/100
81 20204 Washington DC 40/100 69/100
82 20206 Washington DC 40/100 69/100
83 20207 Washington DC 40/100 69/100
84 20208 Washington DC 40/100 69/100
85 20210 Washington DC 40/100 69/100
86 20211 Washington DC 40/100 69/100
87 20212 Washington DC 40/100 69/100
88 20213 Washington DC 40/100 69/100
89 20214 Washington DC 40/100 69/100
90 20215 Washington DC 40/100 69/100
91 20216 Washington DC 40/100 69/100
92 20217 Washington DC 40/100 69/100
93 20218 Washington DC 40/100 69/100
94 20219 Washington DC 40/100 69/100
95 20220 Washington DC 40/100 69/100
96 20221 Washington DC 40/100 69/100
97 20222 Washington DC 40/100 69/100
98 20223 Washington DC 40/100 69/100
99 20224 Washington DC 40/100 69/100
100 20226 Washington DC 40/100 69/100

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: 2026-06-04.

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 →

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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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