Compared to statewide averages in CA, Rancho Santa Margarita scores well - health violations are below the norm and systems generally operate within federal standards.

Data: EPA SDWIS

Overview

We track home safety data for 1 ZIP code in Rancho Santa Margarita, California (population ~43,937), covering 2 community water systems serving approximately 181,948 people region-wide. The EPA snapshots used for this build directly map water systems to 1 of 1 ZIP codes.

The available EPA record reports 0 violations for 1 ZIP code with a reported violation count.

Home Safety Score

Average Home Safety Score for Rancho Santa Margarita: A (92/100)

Model 4.0.0 uses four measured components across three equally weighted domains. If a required domain is unavailable, no score is published:

Factor	What It Measures
Water Quality	EPA violations and compliance history
PFAS MCL Screen	UCMR 5 testing against the covered federal MCLs
Radon Risk	EPA radon zone classification
Annual AQI	EPA AirData county-year median with at least 90 observed days

Water Sources

Rancho Santa Margarita water systems draw from: Surface water.

Lead & Copper

• Average lead level (90th percentile): 0.0039 mg/L (EPA action level: 0.015 mg/L)
• 0 of 1 ZIP code with known status exceed the EPA lead action level

Radon Risk

Dominant radon zone: Zone 3 (Low Risk)

Areas with No Violations

All ZIP Codes in Rancho Santa Margarita

• 92688 [A]

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

Reporting periods vary by source. Missing data is shown as unavailable, not as zero.

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.

1997

Median Year Built

23%

Pre-1986 (Lead Paint Risk)

1%

Pre-1970 (Lead Pipes Risk)

Pre-1970 (1%) 1970–1986 (22%) Post-1986 (77%)

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

23%

Homes Built Before 1986

0.0039

mg/L Avg Lead (Limit: 0.015)

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.