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RadonVerdict

County evidence note

Radon zone and test data for Los Angeles County, CA

County data can show why testing matters. It cannot tell you the radon level in a particular house. The only property-level answer comes from a valid test.

What the source supports

Los Angeles County looks lower at county level, but the home still needs its own number.

Los Angeles County, CA is measurement-backed for 2008-2017. The measured average is 1.9 pCi/L, and 9.5% of reported results are at or above 4.0 pCi/L. The high-end signal reaches 363.7 pCi/L.

Source hierarchy: CDC Tracking Network is used for this county, with EPA zone and Census housing data kept as supporting context. CDC Tracking provides comparable county-level measurement fields; state-specific sources still outrank it when they expose stable county tables.

EPA map zone: Zone 2

The EPA map predicts broad county potential; it is not a measurement for an address.

Source: CDC Environmental Public Health Tracking Network Radon Tests from Labs

Coverage: 2008-2017 ยท retrieved 2026-05-05

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What to do with this information

  1. 1. Test the homeUse a valid device and record duration, placement, and conditions.
  2. 2. Interpret the resultTreat 4.0 pCi/L as the main action threshold and preserve the testing context.
  3. 3. Use qualified helpFor testing or mitigation, use state requirements and recognized proficiency programs.

Evidence profile for Los Angeles County

Reported average1.9 pCi/L
At or above 4.09.5%
Source test volume1,367 over 10 years
Comparison cohort58

CDC Tracking provides comparable county-level measurement fields; state-specific sources still outrank it when they expose stable county tables.

Nearby comparison: Closest counties by county average: Solano County (1.8 pCi/L) is just lower, and Monterey County (1.9 pCi/L) is just higher.

Intent-matched guide

Open the page that answers the actual search

Commercial testing protocol

Editorial and Data Transparency

Author
RadonVerdict (Independent public-data software project)
Evidence Review
Official and primary sources cited below
Data Retrieved At
2026-02-24

Primary Sources