Worst Infrastructure: California

Out of 2,432 ZIP codes with infrastructure data in California, these areas face the highest estimated risk of water pipe failure based on infrastructure age, funding gaps, and violation history.

Statistic	Value
ZIP codes ranked	2,432
Highest risk	70%
Median risk	38%
Average risk	37%
State	California

Top 100 Highest Risk ZIP Codes

Rank	ZIP Code	City	State	Pipe Failure Risk	Risk Level	Safety Score
1	94021	Loma Mar	CA	70%	Very High	83/100
2	94512	Birds Landing	CA	68%	Very High	73/100
3	95325	Hornitos	CA	68%	Very High	53/100
4	95419	Camp Meeker	CA	66%	Very High	98/100
5	94569	Port Costa	CA	65%	Very High	73/100
6	93943	Monterey	CA	63%	Very High	73/100
7	94707	Berkeley	CA	63%	Very High	63/100
8	95720	Kyburz	CA	63%	Very High	50/100
9	95950	Grimes	CA	63%	Very High	58/100
10	96009	Bieber	CA	62%	Very High	97/100
11	91104	Pasadena	CA	61%	Very High	81/100
12	91125	Pasadena	CA	61%	Very High	81/100
13	94940	Marshall	CA	61%	Very High	73/100
14	92332	Essex	CA	60%	High	53/100
15	93741	Fresno	CA	60%	High	73/100
16	94950	Olema	CA	60%	High	73/100
17	94577	San Leandro	CA	59%	High	58/100
18	94937	Inverness	CA	59%	High	88/100
19	95550	Korbel	CA	59%	High	66/100
20	95601	Amador City	CA	59%	High	63/100
21	95735	Twin Bridges	CA	59%	High	53/100
22	95957	Meridian	CA	59%	High	65/100
23	91107	Pasadena	CA	58%	High	76/100
24	91316	Encino	CA	58%	High	23/100
25	93106	Santa Barbara	CA	58%	High	64/100
26	93541	Lee Vining	CA	58%	High	71/100
27	93563	Valyermo	CA	58%	High	78/100
28	94525	Crockett	CA	58%	High	66/100
29	94702	Berkeley	CA	58%	High	63/100
30	94708	Berkeley	CA	58%	High	55/100
31	95018	Felton	CA	58%	High	55/100
32	95380	Turlock	CA	58%	High	65/100
33	95486	Villa Grande	CA	58%	High	65/100
34	95494	Yorkville	CA	58%	High	66/100
35	94116	San Francisco	CA	57%	High	54/100
36	94578	San Leandro	CA	57%	High	58/100
37	94705	Berkeley	CA	57%	High	63/100
38	94709	Berkeley	CA	57%	High	63/100
39	95319	Empire	CA	57%	High	53/100
40	95564	Samoa	CA	57%	High	66/100
41	90073	Los Angeles	CA	56%	High	78/100
42	90806	Long Beach	CA	56%	High	70/100
43	91103	Pasadena	CA	56%	High	76/100
44	91201	Glendale	CA	56%	High	83/100
45	91436	Encino	CA	56%	High	18/100
46	94108	San Francisco	CA	56%	High	59/100
47	94117	San Francisco	CA	56%	High	53/100
48	94122	San Francisco	CA	56%	High	59/100
49	94127	San Francisco	CA	56%	High	59/100
50	94576	Deer Park	CA	56%	High	66/100
51	94579	San Leandro	CA	56%	High	53/100
52	94703	Berkeley	CA	56%	High	63/100
53	94964	San Quentin	CA	56%	High	66/100
54	95606	Brooks	CA	56%	High	73/100
55	95613	Coloma	CA	56%	High	55/100
56	96115	Lake City	CA	56%	High	66/100
57	90270	Maywood	CA	55%	High	72/100
58	92102	San Diego	CA	55%	High	60/100
59	93247	Lindsay	CA	55%	High	28/100
60	94010	Burlingame	CA	55%	High	67/100
61	94112	San Francisco	CA	55%	High	54/100
62	94114	San Francisco	CA	55%	High	59/100
63	94118	San Francisco	CA	55%	High	59/100
64	94123	San Francisco	CA	55%	High	59/100
65	95202	Stockton	CA	55%	High	77/100
66	95471	Rio Nido	CA	55%	High	60/100
67	95690	Walnut Grove	CA	55%	High	75/100
68	95721	Echo Lake	CA	55%	High	53/100
69	95910	Alleghany	CA	55%	High	83/100
70	90704	Avalon	CA	54%	High	83/100
71	90742	Sunset Beach	CA	54%	High	65/100
72	91207	Glendale	CA	54%	High	83/100
73	92106	San Diego	CA	54%	High	60/100
74	92107	San Diego	CA	54%	High	60/100
75	92116	San Diego	CA	54%	High	60/100
76	92312	Barstow	CA	54%	High	39/100
77	92356	Lucerne Valley	CA	54%	High	69/100
78	93539	Lancaster	CA	54%	High	36/100
79	93584	Lancaster	CA	54%	High	36/100
80	93586	Lancaster	CA	54%	High	36/100
81	93613	Clovis	CA	54%	High	73/100
82	93923	Carmel	CA	54%	High	68/100
83	94104	San Francisco	CA	54%	High	59/100
84	94110	San Francisco	CA	54%	High	59/100
85	94121	San Francisco	CA	54%	High	59/100
86	94129	San Francisco	CA	54%	High	53/100
87	94501	Alameda	CA	54%	High	55/100
88	94706	Albany	CA	54%	High	63/100
89	95060	Santa Cruz	CA	54%	High	48/100
90	95204	Stockton	CA	54%	High	72/100
91	96038	Grenada	CA	54%	High	88/100
92	96068	Nubieber	CA	54%	High	73/100
93	96110	Eagleville	CA	54%	High	66/100
94	90807	Long Beach	CA	53%	High	70/100
95	90810	Long Beach	CA	53%	High	70/100
96	90814	Long Beach	CA	53%	High	70/100
97	91108	San Marino	CA	53%	High	76/100
98	91205	Glendale	CA	53%	High	83/100
99	91330	Northridge	CA	53%	High	53/100
100	91962	Pine Valley	CA	53%	High	45/100

Methodology

Infrastructure risk rankings combine four data sources, each weighted equally (25%): (1) EPA Drinking Water Infrastructure Needs Survey (DWINS 2023) — state-level 20-year funding gap per capita for pipe replacement, treatment, and storage; (2) Census ACS housing vintage — percentage of homes built before 1980, when lead solder and galvanized pipes were common; (3) EPA SDWIS violation and enforcement data — system-level compliance history; (4) Lead and Copper Rule indicators — service line material inventories and 90th percentile lead testing results. The combined score is normalized to a 0-100% probability scale.

Data sources: EPA DWINS 2023, Census ACS, EPA SDWIS, Lead and Copper Rule data. Last updated: 2026-07-19.

Frequently Asked Questions

What does pipe failure probability mean?

Pipe failure probability estimates the likelihood of water main breaks, lead contamination from corroded pipes, or service disruptions based on infrastructure age, state funding gaps, violation history, and lead indicators. It is not a prediction of imminent failure, but a risk assessment based on known factors.

How is infrastructure risk calculated?

The risk score combines four equally weighted factors: state-level infrastructure funding gap per capita (from EPA DWINS 2023), housing vintage (Census ACS pre-1980 housing percentage), water system violation and enforcement history (EPA SDWIS), and lead exposure indicators (service line probability and testing results).

What can homeowners do about aging infrastructure?

Test your tap water annually, especially for lead. Check if your home has a lead service line through your water utility. Consider a whole-house water filter (NSF/ANSI 53 certified). Review your water system Consumer Confidence Report for violation history.

Does high risk mean my water is unsafe right now?

Not necessarily. Infrastructure risk indicates long-term vulnerability, not current contamination. However, areas with aging pipes and high violation counts have a statistically higher chance of water quality issues. Regular testing is the best way to verify your water safety.

Worst Infrastructure: California — 2026 Rankings