Commercial Radon Cost Guide, Los Angeles

What Commercial Radon Work Actually Costs in Los Angeles

Commercial radon mitigation in Los Angeles typically costs $6,500 to $28,000, and commercial radon testing costs $650 to $1,800 for a small building or $45 to $110 per unit for multifamily. Everything below explains what moves those numbers, because the ranges are wide for real reasons.

Most contractors in this trade will not publish numbers at all. We think that is mostly about protecting margin, and it wastes a lot of everybody's time on the phone. Here is what we charge and why.

Testing Costs

Scope	Price range	Notes
Small commercial building (under ~10,000 sq ft)	$650–$1,100	Continuous monitors, 48–96 hours, report in 2–3 business days
Larger commercial building	$1,100–$1,800	Device count driven by ground-contact occupied rooms
Multifamily, per unit tested	$45–$110	Per-unit price falls as count rises; one mobilization either way
School campus, ~30 classrooms	$2,200–$4,800	Ground-contact rooms only; includes plain-language summary
Post-mitigation verification	$350–$700	Included in our mitigation contracts
Rush / weekend scheduling	+20–40%	Due diligence windows, closing deadlines

Mitigation Costs

Scope	Price range	What drives it
Single-slab commercial building	$6,500–$12,000	2–4 suction points, straightforward routing
Larger or complex single building	$12,000–$18,000	More points, longer runs, roof coordination
Multi-building or multi-slab property	$14,000–$28,000+	Each separate slab is effectively its own system
Crawl space, sub-membrane	$12–$22 per sq ft	Pier count, headroom, debris removal
HVAC pressurization solution (offices)	$1,500–$6,000	Balancing and verification only, where it works
Vapor intrusion system	+30–70% over radon	Sampling ports, monitoring, alarms, OM&M plan
LADBS methane, Level I	$4–$7 per sq ft of slab	Barrier, gravel blanket, passive venting
LADBS methane, Level V	$18–$30 per sq ft of slab	Full active system, sensors, alarms, trench dams, deputy inspection
New construction soil gas (radon focus)	$2.50–$6.00 per sq ft	Installed during slab prep; a fraction of retrofit

The Six Things That Move Your Price

1. Suction point count. The single biggest variable, determined by sub-slab communication testing, not by square footage. A 1990s tilt-up over clean aggregate might develop a 60-foot pressure field from one point. A 1955 slab on native clay might reach twelve feet.
2. Number of separate slabs. An eleven-building garden apartment property is eleven systems, not one. This surprises owners more than anything else on the list.
3. Routing. A clean shot up a mechanical shaft is cheap. Fire-rated penetrations through occupied corridors are not.
4. Roof work. Membrane roofs under warranty need a roofer to make the penetration. Add $800 to $2,500.
5. Occupancy constraints. Night, weekend, school-break, and healthcare containment work costs 20% to 60% more in labor and is almost always worth it.
6. Which contaminant. A radon system is done at verification. A vapor intrusion system enters a monitoring program that costs $3,000 to $12,000 a year, indefinitely.

Multifamily, Per Unit

The per-unit framing is how lenders and owners think about it, so: industry modeling published through AARST in 2025 put mitigation at roughly $2,400 to $4,000 per affected unit, and on a 155-unit example property that spread to about $387 to $645 per unit across the whole asset. Our own LA numbers track that. What the per-unit framing hides is that mitigation follows slabs, not doors, so a building with four elevated units and a building with fourteen may cost the same to fix.

The Costs People Forget

• Annual monitoring on regulated systems. $3,000 to $12,000 a year on a vapor intrusion site. This recurs forever until case closure.
• Deputy inspection on methane projects. Required at Site Design Level II and above, hired by the GC, paid by the owner.
• Re-test cycles. Usually every two years for radon systems under a lender O&M plan.
• Fan replacement. $850 to $1,600 every 8 to 12 years, per fan.
• Schedule cost. The most expensive radon problem we see is not the mitigation. It is the two-week loan extension caused by starting the testing conversation on day 18 of a 30-day due diligence window.

Where to Verify This Independently

You do not have to take a contractor's word on any of it. The U.S. EPA radon program publishes the action level and the standards of practice the industry works to. The California Department of Public Health radon services certification page explains exactly what certification and contractor licensing a company must hold to do this work in California, and lists who holds it. Check any bidder against that list, including us.

Cost Questions We Get Constantly

How much does commercial radon mitigation cost in Los Angeles?

Between $6,500 and $28,000 for most commercial buildings, with the number driven almost entirely by suction point count and the number of separate slabs. A single-slab building with good sub-slab communication sits near the bottom; a multi-building apartment property is effectively several systems and prices accordingly.

Why can't you quote over the phone?

Because the biggest cost variable is invisible from an address. Two identical 40,000 square foot buildings can need two suction points or nine depending on what is under the slab, and the only way to know is a communication test on site. We can give you a range on the phone and we do, but the fixed price follows the visit.

How much does commercial radon testing cost?

$650 to $1,800 for a small commercial building, and $45 to $110 per unit for multifamily with the per-unit price dropping as unit count rises. Post-mitigation verification testing runs $350 to $700.

What does it cost to run the system?

A commercial radon fan draws roughly 60 to 180 watts continuously, which is about $90 to $260 a year per fan at current LA commercial electricity rates. Fans last 8 to 12 years and cost $850 to $1,600 to replace.

Is methane mitigation more expensive than radon mitigation?

Usually, and sometimes dramatically. LADBS Division 71 methane systems are priced by Site Design Level: roughly $4 to $7 per square foot of slab at Level I, and $18 to $30 per square foot at Level V where mechanical depressurization, sensors, alarms and trench dams are all required, plus deputy inspection fees. Radon systems are performance-based and generally cost less.

Are there financing or tax treatments for this?

For commercial property, mitigation is typically a capital improvement rather than a deductible repair, which your CPA should confirm for your situation. We are not accountants and will not pretend otherwise. On acquisitions, the more common financial mechanism is a seller credit or escrow holdback rather than financing.