Granite Bay, CA Water Safety: 73/100 (2026)
1 ZIP code · 8 water systems · Updated 2026-06-03
Water systems serving Granite Bay hold a strong EPA compliance record — the city places among the better-performing areas in CA with few health-based violations on file.
How Granite Bay Compares
Data: EPA SDWIS Last verified: 2026-06-03
What You Should Know About Granite Bay Water
- Average lead level: 0.003 mg/L.
- Homes built before 1986: 44% — older plumbing may contain lead solder.
- Estimated remediation: $2,200 per household.
- CDC health risk index: 11.13.
Who Supplies Your Water in Granite Bay
Residential water service in Granite Bay, CA is divided among 3 separate utilities, drawn from 8 systems on file with federal regulators.
Overview
We track water quality and home safety data for 1 ZIP code in Granite Bay, California (population ~22,549), covering 8 community water systems serving approximately 276,262 people region-wide.
No EPA violations recorded across any ZIP codes in Granite Bay — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Granite Bay: B (73/100)
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
Granite Bay water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0030 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 |
|---|---|---|---|
| 95746 | B | San Juan Water District | 29,598 |
All ZIP Codes in Granite Bay
- 95746 [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.
Health Outcomes in Granite Bay
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
Housing & Infrastructure in Granite Bay
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
For a city with a median build year of 1981, Granite Bay carries a housing profile that straddles the 1986 federal ban on lead solder in plumbing. Neither predominantly new nor predominantly old, the stock presents a moderate aggregate risk environment — with individual risk varying sharply depending on when and where a specific home was built.
Most homes in Granite 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.
Cost Context: What Remediation Means for Granite Bay Homeowners
Low proportionality — that's the Granite Bay picture when remediation costs are placed against typical home equity.
Remediation costs in Granite Bay are relatively low compared to home values. The $1,200–$3,300 estimated range is a small fraction of median property value. Home values are 43% above the California average.
Lead Exposure Risk for Children in Granite Bay
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 Granite Bay. 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.
Flood & Climate Risk in Granite Bay
A moderate NFIP record for Granite Bay — 118 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.
Granite Bay has a moderate flood history with 118 FEMA claims averaging $29,120 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>$2,200</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 Granite Bay, CA