Radon Testing and Monitoring · Los Angeles

Radon testing and monitoring
for Los Angeles homes.

Radon is invisible, odorless, and easy to ignore. Baseline helps homeowners understand their risk, measure properly over time, and know when action is needed.

Serving Woodland Hills, the San Fernando Valley, and surrounding Los Angeles communities.

The Invisible Risk

You cannot smell radon.
You cannot feel it.
You have to measure it.

Radon is a naturally occurring radioactive gas that can enter homes through soil contact, foundation cracks, crawlspaces, and other pathways. It is widely recognized as a significant lung cancer risk factor, especially because it often goes unnoticed for years. There are no symptoms that tell you it is there.

The EPA sets an action level of 4.0 pCi/L. Average indoor levels in the US are around 1.3 pCi/L. Levels in individual homes can be much higher. The only way to know your home's actual level is to measure it, over enough time for the reading to be meaningful.

Why This Matters to Baseline

Our family only found out
because of a chance conversation.

In 2022, a casual online discussion about indoor air quality led to a question we had never thought to ask. We decided to test our home in West Hills. The result was nearly four times the EPA's recommended action level. Our kids had been in that house. We had no symptoms, no warning, and no reason to know without testing.

We addressed it. We also started asking what else might be happening in the home's air that no one had ever measured. That question became Baseline.

Baseline exists because protecting your family's health should not depend on a lucky thread.
14 pCi/L
Radon level found in the Baseline founder's West Hills home. The EPA action level is 4.0 pCi/L.
4.0 pCi/L
EPA action level for radon. Levels at or above this threshold warrant mitigation consideration.
2nd
Leading cause of lung cancer in the US, after smoking. Estimated to cause roughly 21,000 deaths per year.
0
Symptoms. Radon produces no visible, physical, or sensory signs of its presence in a home.
Los Angeles highway obscured by wildfire smoke and orange haze

Southern California

No color. No odor. No symptoms.
Measurement is the only signal.

California homes

California homes can have radon too.

Many homeowners assume radon is primarily a Midwest or East Coast problem. That assumption is not reliable. Radon levels vary from home to home based on geology, foundation type, ventilation patterns, soil contact, pressure differences, and construction details. Two homes on the same street can have very different readings.

The only reliable way to understand your home's radon level is to measure it directly, over a meaningful time period.

Risk can differ significantly between neighboring homes. Your neighbor's test result says nothing about what is happening in your home.

Prior low readings do not always represent long-term or seasonal conditions. Radon levels can shift with weather, season, ventilation changes, and soil pressure.

Continuous monitoring provides a more complete picture than a single snapshot. Trends over time are more informative than one reading taken on one day.

Homes with slab foundations, crawlspaces, basements, or significant soil contact carry elevated baseline risk factors worth understanding.

A Better Picture Over Time

Radon is not a
one-moment problem.

Radon levels can shift with season, weather, ventilation, foundation pressure, and home operation. A credible radon strategy should respect dwell time and long-term patterns, not just a single snapshot.

Option 1

Short-Term Screening

Typically 48-96 hours. Useful as an initial signal to identify whether further testing is warranted. Limited in reliability because radon levels vary with short-term conditions. Closed-house protocols help, but variability remains.

Option 2

Certified Testing

Appropriate when a formal, documented result is needed for real estate transactions, compliance, insurance purposes, or when a remediation decision requires a certified finding. Performed by a licensed radon measurement professional.

Option 3

Continuous Monitoring

Sensor installed in the home over months or seasons. Captures seasonal variation, confirms that levels remain within an acceptable range, and provides ongoing visibility for homeowners who want a complete picture of their home's air over time.

Baseline Approach

Risk Review, Monitoring, and Referral

During the assessment, Baseline documents foundation type, crawlspace conditions, soil contact, and ventilation patterns that influence radon entry. Ongoing monitoring is available as a membership upgrade. When sustained readings cross the EPA action level, Baseline refers to a certified mitigator. All data belongs to the homeowner.

Measured, Careful, and Honest

Baseline does not
pretend to capture a definitive picture from a quick visit.

A 90-minute assessment can identify risk factors and take an initial reading. It cannot substitute for the dwell time a credible radon evaluation requires.

Radon risk review
Foundation type, crawlspace conditions, soil contact, and lower-level ventilation are observed and documented in the Baseline Report.
Optional continuous radon monitoring
Available as a membership upgrade. A dedicated radon monitor provides ongoing readings over time, capturing seasonal variation and longer-term trends.
Readings belong to the homeowner
All data from monitoring is yours. You can share it with a real estate agent, a mitigator, a physician, or anyone else you choose.
Referral when action is needed
If sustained readings cross the EPA action level of 4.0 pCi/L, Baseline refers the homeowner to a certified mitigator for confirmation and remediation planning.
Post-mitigation confirmation
Continuous monitoring confirms whether a mitigation system is working correctly over time.

Is this for you?

Homes that benefit most
from radon monitoring.

These are situations where radon monitoring provides clear value. If one or more applies to your home, it is worth understanding your risk.

Slab foundations, crawlspaces, or basements

Homes with significant soil contact are the most common pathway for radon entry. Foundation type is one of the primary risk factors reviewed during a Baseline assessment.

San Fernando Valley, West Hills, Woodland Hills, Simi Valley

Homeowners in these communities who want better visibility into their home's radon risk. Local geology varies and individual home conditions matter more than regional averages.

Prior elevated radon readings

If a prior test returned an elevated result but mitigation was not pursued, or if the result was borderline, ongoing monitoring provides a clearer picture than a single historical reading.

Homes that have completed mitigation

Mitigation systems can shift in effectiveness over time. Continuous monitoring confirms that the system continues to perform and alerts the homeowner if levels increase.

Families who want a complete air quality picture

Radon is one part of a broader set of indoor air risks that includes PM2.5, VOCs, CO2, humidity, and combustion gases. Baseline brings these signals together in a single picture of the home.

New homeowners or recent renovation

Purchasing a home or completing structural work changes the risk profile. Prior owners may not have tested, and construction activity can disturb soil pathways. A fresh baseline is appropriate.

The bigger picture

Radon belongs in the larger home health picture.

Radon is one part of a broader indoor air picture that includes fine particulate matter, VOCs, carbon dioxide, humidity, temperature, carbon monoxide, ventilation, and filtration. Baseline brings these signals together so the homeowner can understand how the home is performing over time, not just in one dimension.

PM2.5
Wildfire smoke, cooking, traffic particulates
VOCs
Chemical off-gassing from materials and products
CO2
Ventilation quality, sleep impact, cognitive effects
Humidity
Respiratory health, mold risk, virus transmission
CO
Combustion appliances, attached garages, low-level exposure
Radon
Soil gas intrusion, long-term lung cancer risk

Service Area

Radon testing and monitoring for Los Angeles homes.

Baseline serves homeowners across Woodland Hills, West Hills, Calabasas, Tarzana, Encino, Sherman Oaks, Studio City, the San Fernando Valley, and surrounding Los Angeles communities within a 50-mile radius.

Common questions

What to know about radon.

Get started

The only way to know
is to measure.

Radon is invisible. Your home's risk should not be invisible too. Start with a Baseline Assessment and understand whether radon belongs in your long-term monitoring plan.

Questions about your home's specific risk factors? Call or text us at 818-237-3404.

CSLB #1153130 · Los Angeles · 818-237-3404

Get in Touch
Questions about radon, the assessment, or whether Baseline is right for your home.

Call or Text 818-237-3404