Radon · Los Angeles & Orange County
Radon Testing
Radon testing measures the concentration of naturally-occurring radioactive gas seeping from soil and bedrock beneath a home — the EPA links long-term radon exposure to about 21,000 lung-cancer deaths a year in the United States. We deploy NRPP-aligned continuous radon monitors over a minimum 48-hour test period and provide written reports keyed to the California CDPH Indoor Radon Program benchmarks.
What is Radon Testing?
Radon (Rn-222) is a colorless, odorless, tasteless radioactive gas produced by the natural decay of uranium in soil and bedrock. It enters a home through foundation cracks, plumbing penetrations, sump pits, crawlspace openings, and any below-grade slab discontinuity, and concentrates indoors when ventilation is insufficient. Long-term exposure above the EPA action level of 4.0 picocuries per liter (pCi/L) measurably increases lung-cancer risk; the World Health Organization recommends a stricter 2.7 pCi/L threshold. Testing combines a short-term continuous monitor placed in the lowest occupied level of the home with optional follow-up 90-day passive devices for confirmation. California's CDPH Indoor Radon Program maintains a voluntary registry mapping county-level potential — Los Angeles County contains multiple census tracts in EPA Zone 2 (moderate potential), making pre-purchase testing a routine step in LA-area transactions.
When You Need It
Anytime you're under contract to buy a California home — radon testing is increasingly included as a standard inspection contingency in LA-area transactions, particularly in hillside neighborhoods (Beverly Hills, Pacific Palisades, Brentwood, Calabasas) where bedrock-proximate construction is common. Also test before remodeling a basement-level space, after a home has been tightened for energy efficiency (modern weatherstripping and impact glazing can trap radon), and any time a long-term occupant develops unexplained respiratory symptoms with no clear allergen source. Existing homeowners should retest every two to five years even after a clean baseline result, because foundation movement, HVAC reconfiguration, and envelope-sealing upgrades can all shift indoor radon levels.
Signs to Watch For
- New home purchase in a Los Angeles hillside or canyon neighborhood
- Recent foundation work, basement remodel, or crawlspace conversion
- Energy-efficiency upgrades that tightened the building envelope
- Persistent unexplained respiratory symptoms in long-term occupants
- Home located in EPA Radon Zone 1 or Zone 2 (parts of LA County qualify)
- Last radon test was more than three to five years ago
- Modified sump pit, crawlspace vent, or French drain inside the envelope
Our Radon Testing Process
1. Pre-test consultation
Confirm home occupancy patterns, HVAC operation, and any open windows or doors over the prior 12 hours. Closed-house conditions for at least 12 hours pre-test are required for accurate short-term radon results per EPA protocol.
2. Monitor placement
NRPP-aligned continuous radon monitor placed in the lowest occupied level of the home, at least 20 inches off the floor, away from drafts, sumps, and exterior walls. Test duration: minimum 48 hours; we recommend 72 hours for tighter confidence intervals.
3. Hour-by-hour data capture
The continuous monitor logs radon concentration every hour plus temperature, humidity, and barometric pressure. Spikes correlate with open-house events; readings stabilize after 24 hours of consistent closed-house conditions. The hourly time series goes into the report so anomalies are explainable.
4. Written report
Lab-grade report includes the hourly time-series chart, the 48- or 72-hour average in pCi/L, comparison to the EPA action level (4.0 pCi/L) and WHO recommended threshold (2.7 pCi/L), and California CDPH benchmark guidance. Delivered within 24-48 hours of monitor retrieval.
5. Mitigation referral (if needed)
If readings exceed 4.0 pCi/L, we provide a written remediation protocol and refer to a California-licensed radon mitigation contractor. Sub-slab depressurization is the most effective approach in single-family residential construction — typical cost $1,500-3,500.
What to Expect
Continuous radon testing in the Los Angeles area runs $185-275 for a single 48-to-72-hour deployment with a written report, depending on home size and accessibility. Pre-purchase inspections that bundle radon testing with mold, lead, and general property inspection typically receive a package discount. Test results are delivered electronically within 24-48 hours of monitor retrieval. If readings exceed the EPA action level of 4.0 pCi/L, mitigation typically costs $1,500-3,500 for sub-slab depressurization in a residential structure — orders of magnitude less than potential downstream cancer-treatment costs. California real-estate transactions increasingly include a radon contingency in the buyer's inspection period; we coordinate directly with your real-estate agent to fit the test inside the standard 17-day California buyer-investigation window.
Common Questions
How fast can you come out for an inspection?
What is radon and why does it matter in California homes?
What is a safe radon level — and when do I need mitigation?
Do you offer radon, lead, and home inspection in addition to mold services?
Areas We Serve
Radon Testing is offered across the Los Angeles Westside, San Fernando Valley, and Orange County. Click your city for local details:
- radon testing in Beverly Hills
- radon testing in Santa Monica
- radon testing in Malibu
- radon testing in Brentwood
- radon testing in West Los Angeles
- radon testing in Pacific Palisades
- radon testing in Calabasas
- radon testing in Encino
- radon testing in Sherman Oaks
- radon testing in Studio City
- radon testing in West Hollywood
- radon testing in Burbank
- radon testing in Glendale
- radon testing in Newport Beach
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