San Marcos, CA: 1 Violation - Home Safety 90/100
4 ZIP codes · 7 water systems · Updated
ZipCheckup grade for San Marcos: A.
Checked records flag no major concern; missing data is unknown.
Within San Marcos, CA, the available records add up to an upper-tier grade; that grade describes records, not the water at a given faucet.
How San Marcos Compares
Data: EPA SDWIS
Key Facts for San Marcos Residents
- Water systems mapped to your city have 1 violation on record since 2021.
- Average of reported 90th-percentile lead results: 0.0009 mg/L.
- Health risk index (ZipCheckup composite of CDC data): 10.18.
San Marcos's Water Providers
Service in San Marcos, CA can differ by address: 7 water systems are tied to the area in federal records, and the 3 largest are listed with their violation records.
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Overview
We track home safety data for 4 ZIP codes in San Marcos, California (population ~100,367), covering 7 community water systems serving approximately 618,883 people region-wide. The EPA snapshots used for this build directly map water systems to 3 of 4 ZIP codes.
3 of 3 ZIP codes with a reported violation count in the available EPA record (100%) have recorded EPA violations. The available record reports no health-based violations for this measured scope.
Home Safety Score
Average Home Safety Score for San Marcos: A (90/100)
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
San Marcos water systems draw from: Surface water.
Lead & Copper
- Average of reported 90th-percentile lead results: 0.0009 mg/L (EPA action level: 0.015 mg/L)
- 0 of 3 ZIP codes with known status exceed the EPA lead action level
Radon Risk
4 of 4 ZIP records with known zones are in EPA Radon Zone 3.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
Top Contaminants
| Contaminant | Category | Violations | ZIPs Affected |
|---|---|---|---|
| Lead and Copper Rule Revisions | Treatment Technique | 4 | 3 |
Areas with Most Violations
| ZIP Code | Safety Score | Violations | Health-Based | System |
|---|---|---|---|---|
| 92069 | A | 1 | 0 | Vallecitos Water District |
| 92078 | A | 1 | 0 | Vallecitos Water District |
| 92096 | — | 1 | 0 | Vallecitos Water District |
All ZIP Codes in San Marcos
- 92069 [A] - 1 violation
- 92078 [A] - 1 violation
- 92079
- 92096 - 1 violation recorded for mapped water systems
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.
San Marcos Community Health Snapshot
Source: CDC PLACES (County-level estimates). County health indicators are shown for context only and are not linked to this area's water records.
Compared to National Average
Vertical line = national average. ■ Above national · ■ Below national
What's in San Marcos's Water?
Based on EPA violation records. Check your ZIP code report for system-specific contaminant data.
San Marcos: Lead Risk & Vulnerable Populations
Why children are most at risk: The CDC states that no safe blood lead level in children has been identified. Children under 6 absorb lead more readily than adults, and even low levels can cause developmental delays, learning difficulties, and behavioral problems.
Available area-level lead records for San Marcos do not determine the lead level at an individual tap. Testing is the only way to confirm your water's lead content.
Sources: EPA Lead and Copper Rule, U.S. Census Bureau ACS, CDC childhood lead poisoning prevention guidelines.
San Marcos: NFIP Claim Records and Water-Quality Context
Historical NFIP data for San Marcos contains 42 flood insurance claims. Among claims with payment data, the average reported building, contents, and ICC component sum is $19,810. Among ZIP codes with claim records, 50% have an A- or V-family dominant rated zone recorded in those historical claims. This is not a complete current FEMA property-map inventory.
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.
Claim count does not establish current property risk. Check the exact address in FEMA's current map and obtain a property-specific insurance quote when relevant.
Source: historical FEMA National Flood Insurance Program (NFIP) claim records. No current FEMA property-map designation is asserted.
Deep Dive Reports
Detailed analysis for San Marcos, CA