Altadena, CA Water Safety: 71/100 (2026)
2 ZIP codes · 5 water systems · Updated 2026-06-03
In current CA EPA data, Altadena's tap water sits in the high-safety tier.
How Altadena Compares
Data: EPA SDWIS Last verified: 2026-06-03
Key Facts for Altadena Residents
- Estimated remediation: $1,600 per household.
- CDC health risk index: 10.71.
Altadena's Water Providers
Residential water in Altadena, CA is supplied by 3 separate utilities — not one centralized authority. Each of those providers operates under its own service territory boundary, maintains its own distribution infrastructure, and files compliance documentation with the EPA on its own timeline. Federal data counts 5 water systems in the area, with these providers collectively accounting for the dominant share of household connections.
Overview
We track water quality and home safety data for 2 ZIP codes in Altadena, California (population ~36,402), covering 5 community water systems serving approximately 194,494 people region-wide.
No EPA violations recorded across any ZIP codes in Altadena — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Altadena: B (71/100)
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
Altadena water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Altadena
- 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 |
|---|---|---|---|
| 91001 | B | Lincoln Avenue Water Company | 16,088 |
| 91003 | B | Lincoln Avenue Water Company | 16,088 |
All ZIP Codes in Altadena
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.
Altadena 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
How Remediation Costs Compare in Altadena
Placing remediation in the context of Altadena'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 Altadena are relatively low compared to home values. The $800–$2,500 estimated range is a small fraction of median property value. Home values are 47% above the California average.
Altadena: Flood History & Water Damage Risk
Flood history in Altadena spans 35 NFIP claims and 50% flood zone coverage — enough to place it in moderate-exposure territory where flood events are genuinely recurring rather than statistical outliers. That distinction matters for water quality assessment because the connection between flooding and water safety is not uniform across communities. In low-exposure areas, flooding rarely generates the conditions needed to compromise treatment or distribution infrastructure. In high-exposure areas, it can do so repeatedly. Moderate-exposure communities sit in between: flood events occur with enough frequency to make periodic infrastructure stress a reasonable concern, particularly for private well owners and residents in lower-elevation FEMA-designated zones.
Altadena has a moderate flood history with 35 FEMA claims averaging $1,555 per payout. 50% 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 Altadena, CA