Antioch, CA Water Safety: 70/100 (2026)
2 ZIP codes · 5 water systems · Updated 2026-06-03
Tap water in Antioch, CA scores well — low violation counts, above-average safety grade.
How Antioch Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Antioch Residents
- Homes built before 1986: 44% — older plumbing may contain lead solder.
- Estimated remediation: $1,900 per household.
- CDC health risk index: 10.72.
Antioch's Water Providers
Water service in Antioch, CA is split across 3 utilities out of 5 tracked federally, each operating its own infrastructure and compliance record.
Overview
We track water quality and home safety data for 2 ZIP codes in Antioch, California (population ~115,759), covering 5 community water systems serving approximately 483,444 people region-wide.
No EPA violations recorded across any ZIP codes in Antioch — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Antioch: B (70/100)
The score combines three factors:
| Factor | What It Measures |
|---|---|
| Water Quality | EPA violations and compliance history |
| Lead Levels | 90th percentile lead concentration vs EPA action level |
| Radon Risk | EPA radon zone classification |
Water Sources
Antioch water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Antioch
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
- Zone 1 (High): 0 ZIP codes
- Zone 2 (Moderate): 2 ZIP codes
- Zone 3 (Low): 0 ZIP codes
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 94509 | C | City of Antioch | 115,074 |
| 94531 | B | City of Antioch | 115,074 |
All ZIP Codes in Antioch
Data Sources
- Water quality: EPA Safe Drinking Water Information System (SDWIS)
- Lead/copper: EPA Lead and Copper Rule sampling data
- Radon: EPA Map of Radon Zones
Updated daily.
Antioch Community Health Snapshot
Source: CDC PLACES (County-level estimates). Water contamination can correlate with respiratory and chronic health conditions.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
Antioch Infrastructure Age
With 44% of homes built before 1986, lead solder in plumbing is a potential concern. The EPA banned lead solder in 1986, but many older homes retain original plumbing.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
Antioch's residential inventory spans multiple construction eras, with the median build year of 1984 landing in a zone where pre- and post-1986 homes are both well represented. That split matters because homes built before 1986 may contain lead-soldered copper joints — a plumbing practice banned that year — while those built before 1970 face the additional possibility of lead pipes in the service line. Whether a specific household sits on the older or newer end of this distribution is the primary variable shaping its individual exposure risk.
Most homes in Antioch were built after 1986, reducing the risk of lead contamination from plumbing. Older homes should still be tested.
Source: U.S. Census Bureau ACS B25034.
How Remediation Costs Compare in Antioch
Property equity in Antioch runs well ahead of estimated remediation costs — a cost-to-value ratio that sits in the low tier, meaning documented water and safety issues here are the kind homeowners can plan to address without treating the expense as a significant budget event relative to what their homes are worth.
Remediation costs in Antioch are relatively low compared to home values. The $1,000–$2,950 estimated range is a small fraction of median property value. Home values are 11% below the California average.
Antioch: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states there is no safe level of lead exposure for children. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Households with kids in the home — for whom CDC guidance places particular weight on minimizing exposure — face a specific local picture in Antioch. 44% of homes here come from the pre-rule era, and aggregate utility samples either approach or cross 0.015 mg/L. A baseline draw-test kit and certified lead-removal filtration are available via retailer networks for households confirming conditions at a specific tap.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Antioch: Flood History & Water Damage Risk
A moderate NFIP record for Antioch — 70 insurance claims paired with 100% of ZIP codes in FEMA flood zones — points to a flood history where water-quality pathways have likely been periodically relevant.
Antioch has a moderate flood history with 70 FEMA claims averaging $26,012 per payout. 100% of ZIP codes fall within FEMA flood zones. Flood events can contaminate drinking water and overwhelm treatment systems.
How flooding affects water quality: Flood events can introduce sewage, agricultural runoff, and industrial chemicals into water supplies. Even after floodwaters recede, contamination can persist in wells and aging infrastructure. Flood damage can add significantly to the estimated <strong>$1,900</strong> remediation cost per household.
Residents in flood-prone areas should consider flood insurance even outside FEMA zones — over 25% of flood claims come from low-to-moderate risk areas. After any flood event, test your water before drinking.
Source: FEMA National Flood Insurance Program (NFIP) claims data, FEMA flood zone designations.
Deep Dive Reports
Detailed analysis for Antioch, CA