Rancho Santa Margarita, CA: 1 Violation — 99/100 (2026)
1 ZIP code · 4 water systems · Updated 2026-06-04
Compared to statewide averages in CA, Rancho Santa Margarita scores well — health violations are below the norm and systems generally operate within federal standards.
How Rancho Santa Margarita Compares
Data: EPA SDWIS Last verified: 2026-06-04
Key Facts for Rancho Santa Margarita Residents
- Your city's water systems recorded 1 violation in the past 5 years.
- Average lead level: 0.0009 mg/L.
- Homes built before 1986: 23% — older plumbing may contain lead solder.
- CDC health risk index: 10.23.
Rancho Santa Margarita's Water Providers
3 water utilities share the residential service territory in Rancho Santa Margarita, CA — out of 4 total systems in federal records.
Overview
We track water quality and home safety data for 1 ZIP code in Rancho Santa Margarita, California (population ~43,937), covering 4 community water systems serving approximately 221,632 people region-wide.
1 of 1 ZIP code (100%) have recorded EPA violations. All violations are monitoring/reporting type.
Home Safety Score
Average Home Safety Score for Rancho Santa Margarita: A (99/100)
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
Rancho Santa Margarita water systems draw from: Groundwater, Surface water.
Lead & Copper
- Average lead level (90th percentile): 0.0009 mg/L (EPA action level: 0.015 mg/L)
- 0 ZIP codes exceed the EPA lead action level
Radon Risk
Dominant radon zone: Zone 3 (Low Risk)
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Haloacetic Acids (HAA5) | Disinfection Byproducts | 2 | 1 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 92688 | A | 1 | 0 | Santa Margarita Water District |
All ZIP Codes in Rancho Santa Margarita
- 92688 [A] — 1 violation
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.
Rancho Santa Margarita 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
What's in Rancho Santa Margarita's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
Rancho Santa Margarita 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
Banned from residential plumbing in 1986, lead solder was a near-universal feature of copper plumbing before that cutoff. In Rancho Santa Margarita, where the median build year is 1997, the majority of housing falls into the post-ban category — though the older fraction of the stock still carries the residual risk that comes with pre-1986 pipe and solder materials.
Most homes in Rancho Santa Margarita 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.
Rancho Santa Margarita: 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.
Despite citywide averages reading cleanly under the federal action threshold, the way utilities pull samples — from a representative subset rather than door-to-door — leaves room for individual buildings with older interior lines to behave differently than the aggregate suggests. With only 23% of Rancho Santa Margarita stock predating the solder rule, that residual subset is small but real, and a draw-test kit gives the only direct read on what comes out of one faucet on a given morning.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
Deep Dive Reports
Detailed analysis for Rancho Santa Margarita, CA