Acquisition Due Diligence Radon Testing

Where Radon Enters a Deal

Usually through the Phase I environmental site assessment. Radon is technically a non-scope consideration under ASTM E1527, meaning it is not part of the standard Phase I, but consultants routinely include it as an additional service when the property type or the lender's requirements call for it. On agency multifamily deals it comes in through the lender's environmental requirements instead.

Occasionally it enters through a buyer's own risk policy, an institutional investment committee checklist, or an insurer. Those are the ones that appear late, because nobody was expecting them.

Compressing the Timeline Without Breaking the Protocol

The measurement period is not negotiable. What we can compress is everything around it:

• Notice. We draft resident or tenant notices the day you call so the 48-hour clock starts immediately rather than after your property manager finds time.
• Devices. Continuous monitors, always, on a transaction. Results are available the hour they come out rather than after lab turnaround.
• Weekend passes. We deploy and retrieve on weekends at a premium. It is cheaper than an extension.
• Direct delivery. Report goes straight to the environmental consultant, not through the buyer, the broker, and back.

Our fastest complete cycle, including mitigation and post-mitigation verification, was nine days on a 40-unit Long Beach property. That is not the normal case and it cost real money in overtime, but it existed.

Who Pays

Not our business, but we get asked constantly, so: testing is nearly always a buyer cost as part of due diligence. Mitigation is where it gets negotiated. Common outcomes we see in LA deals are a seller credit at closing, an escrow holdback pending completed mitigation and verification, a price adjustment, or the buyer absorbing it as a capital item because the number turned out to be smaller than the argument.

What helps is a written scope with a fixed price early, because a specific number ends a negotiation that a vague range prolongs. We will produce that scope inside 48 hours of walking the property, and we will produce it knowing it might be handed to the other side.

What a Clean Result Is Worth Later

A signed, protocol-correct radon report on a Los Angeles property has a shelf life measured in years for practical purposes. It answers the same question again at refinance, at the next sale, and in a tenant EHS review, provided nothing structural changed.

Sellers who test proactively before going to market get two advantages: they remove an unknown that buyers price defensively, and they control the timeline rather than reacting to it. In a low-radon county where most results come back clean, that is a cheap piece of deal insurance.

Working With Your Consultant

We work under or alongside environmental consultants on most due diligence engagements and have no interest in getting between you and yours. They scope, we measure and mitigate, they report. Our documentation is formatted to drop into their deliverable, and we are used to their review comments.

If you do not have a consultant and just need a defensible radon measurement, we do that directly.

Cost

Standard due diligence testing prices the same as any commercial test, $650 to $1,800 for a small building or $45 to $110 per unit for multifamily. Rush scheduling, weekend passes, and expedited reporting typically add 20% to 40%. Mitigation scoping with a fixed-price proposal inside 48 hours of a site visit is free; we would rather spend an hour to be the contractor on the eventual job.

Questions About This Service

How fast can you test a property in a due diligence window?

Deployment can usually happen within 48 to 72 hours of your call, and with continuous monitors the data is available the moment devices come out. Realistically, plan on 7 to 10 days from call to report for a normal engagement, and 4 to 6 days with rush scheduling and weekend passes.

Is radon part of a standard Phase I ESA?

No. Radon is a non-scope consideration under ASTM E1527, so it is only included when the client, the lender, or the property type calls for it as an additional service. On agency multifamily deals it typically comes in through the lender's separate environmental requirements rather than through the Phase I itself.

Who pays for radon mitigation, buyer or seller?

It is negotiated, and in Los Angeles deals we most often see a seller credit at closing or an escrow holdback pending completed mitigation and verification. Having a fixed-price written scope early tends to shorten that negotiation considerably, because a specific number is harder to argue with than a range.

Should a seller test before going to market?

In a low-radon county like Los Angeles, usually yes. Most results come back clean, which removes an unknown that buyers otherwise price defensively, and it puts the seller in control of the timeline rather than reacting to a buyer's consultant on day 18 of a 30-day window.

Can you deliver the report directly to our environmental consultant?

Yes, and we prefer it. Fewer hands, fewer days. We are used to consultant review comments and format our documentation to drop into their deliverable.