Guasti, CA Water Safety: 53/100 (2026)
1 ZIP code · 1 water system · Updated 2026-06-03
Guasti, CA water systems: poor compliance record, lower-tier safety grade.
How Guasti Compares
Data: EPA SDWIS Last verified: 2026-06-03
Guasti Water: The Quick Version
- Estimated remediation: $400 per household.
- CDC health risk index: 11.58.
Water Systems Serving Guasti
The structure of water supply in Guasti, CA is straightforward: one utility provides the bulk of residential service among 1 tracked system, concentrating rate-setting and infrastructure decisions under a single organization.
Overview
We track water quality and home safety data for 1 ZIP code in Guasti, California, covering 1 community water system serving approximately 185,010 people.
No EPA violations recorded across any ZIP codes in Guasti — an excellent indicator of water quality.
Home Safety Score
Average Home Safety Score for Guasti: D (53/100)
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
Guasti water systems draw from: Surface water.
Lead & Copper
- Lead data: not yet available for Guasti
- 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 |
|---|---|---|---|
| 91743 | D | ONTARIO MUNICIPAL UTILITIES COMPANY | 185,010 |
All ZIP Codes in Guasti
- 91743 [D]
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.
CDC Health Data for Guasti
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
What You Can Do in Guasti
- Test your water at home. City-level data shows averages — your tap may differ. NSF-certified test kits cost $20-40 and give results in days.
- Install a certified water filter. An NSF-certified pitcher or under-sink filter removes most common contaminants.
- Check your home's plumbing. Homes built before 1986 may have lead solder in pipes. A licensed plumber can assess your risk.
- Review your water system's CCR. Your utility publishes an annual Consumer Confidence Report with detailed test results. Request it or find it online.
Deep Dive Reports
Detailed analysis for Guasti, CA