Discovery Bay, CA Water Safety: 78/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
EPA compliance records for Discovery Bay tell a largely clear story: violation rates are low, health-based exceedances are uncommon, and the city's grade puts it well above average within CA.
How Discovery Bay Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Discovery Bay Residents
- Average lead level: 0.0038 mg/L.
- Homes built before 1986: 27% — older plumbing may contain lead solder.
- Estimated remediation: $1,600 per household.
- CDC health risk index: 10.72.
Discovery Bay's Water Providers
In Discovery Bay, CA, the drinking water supply is organized under a single dominant utility — a consolidated structure that shapes how infrastructure investment, regulatory compliance, and rate decisions flow to households. When one provider handles the overwhelming share of residential connections out of 1 tracked system, accountability is clear: service upgrades, EPA violation responses, and tariff changes all funnel through that single organizational structure.
Overview
We track water quality and home safety data for 1 ZIP code in Discovery Bay, California, covering 1 community water system serving approximately 15,316 people.
No EPA violations recorded across any ZIP codes in Discovery Bay — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Discovery Bay: B (78/100)
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
Discovery Bay water systems draw from: Groundwater.
Lead & Copper
- Average lead level (90th percentile): 0.0038 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Areas with No Violations
| ZIP Code | Safety Score | System | Population |
|---|---|---|---|
| 94505 | B | Town of Discovery Bay | 16,790 |
All ZIP Codes in Discovery Bay
- 94505 [B]
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.
Discovery Bay 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
Discovery Bay Infrastructure Age
Housing age data helps assess potential lead pipe and infrastructure risks. Newer housing stock generally means lower plumbing-related contamination risk.
Source: U.S. Census Bureau American Community Survey (ACS).
Housing Age Profile
For most of Discovery Bay's housing stock, construction occurred after 1986 — when lead solder in plumbing was federally prohibited. The median build year of 1994 broadly reflects that newer profile.
Most homes in Discovery Bay 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 Discovery Bay
Placing remediation in the context of Discovery Bay's property market, the equity share is low — most homeowners here are weighing a financial commitment that fits comfortably within routine property planning, far from the threshold where remediation becomes a material equity decision rather than a standard upkeep consideration.
Remediation costs in Discovery Bay are relatively low compared to home values. The $800–$2,600 estimated range is a small fraction of median property value. Home values are 7% above the California average.
Discovery Bay: 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.
Generally, the structural picture for Discovery Bay runs in a quiet direction. Aggregate sampling rests under the federal action benchmark, and 27% of housing comes from the pre-rule era — a contained local footprint. That dual signal keeps lead in the background of local concerns, while a one-faucet measurement still answers a different question than any system average can: what is actually flowing from one specific tap on a given morning.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Discovery Bay: Flood History & Water Damage Risk
Flood activity in Discovery Bay is neither negligible nor at the level of the highest-exposure areas in the NFIP dataset. The 21-claim record and 100% flood zone coverage suggest a community that has experienced recurrent events but has not faced the kind of sustained, severe exposure where water-supply contamination becomes a primary public health concern. It sits in a middle range where flood history merits inclusion in any complete local water quality picture.
Discovery Bay has a moderate flood history with 21 FEMA claims averaging $7,628 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>$1,600</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 Discovery Bay, CA