Radon mitigation cost

A radon mitigation system costs $800 to $2,500 installed, typically around $1,400. A test kit costs $15 to $40 and takes three days. Given that radon is the second leading cause of lung cancer in the United States, the test is the cheapest health decision a homeowner makes.

Roughly one house in fifteen nationally is above the EPA action level, and in some regions it is one in three.

What it costs

Testing, which comes first

Radon is a colorless, odorless radioactive gas from uranium decay in soil. It enters through cracks, the slab-wall joint, sump pits and any penetration.

Short-term test: 2 to 7 days, a charcoal canister or an electret, closed-house conditions. Cheap and quick, and it is a snapshot. Levels vary with weather, season and whether the windows have been open.

Long-term test: 90 days to a year, alpha track detector. More representative of your actual exposure and the better basis for a decision.

The EPA action level is 4.0 picocuries per liter, and the EPA notes there is no level known to be safe. Between 2 and 4, mitigation is worth considering.

Test the lowest lived-in level of the house. Test again after any foundation work, after finishing a basement, and every two years otherwise. Levels change.

How mitigation works

Sub-slab depressurization is the standard system and it is more elegant than it sounds. A pipe is cut through the basement floor into the gravel beneath, a fan pulls a slight vacuum under the slab, and the soil gas is vented above the roof line instead of being drawn into the house.

It works because the house is normally at slightly lower pressure than the soil, which is what draws radon in. Reversing that pressure difference stops it at the source.

A correct installation includes:

• The suction point in the right place, sometimes more than one on a large or divided slab
• Sealing the sump lid, floor cracks and penetrations, so the fan is not just pulling basement air
• The fan in an unconditioned space, attic or outside, never in a basement, because a leak in the positive-pressure side would discharge radon into the house
• Discharge above the roof eave and away from windows
• A manometer on the pipe showing the system is running
• A retest afterwards, which is how anyone knows it worked

Systems typically bring levels down by 80 to 99%.

Frequently asked questions

Is radon really a serious risk?

The EPA attributes roughly 21,000 lung cancer deaths a year in the United States to radon, making it the second leading cause after smoking and the leading cause among non-smokers. It is one of the better-established environmental health risks.

Does my region have radon?

Every state has houses above the action level. Regional maps show tendencies rather than answers, and neighboring houses frequently differ substantially. There is no substitute for testing your own.

Can I install a system myself?

The physical work is achievable and the design is not: suction point placement, fan sizing and sealing decide whether it works. Several states require licensed mitigators. Where DIY is permitted, retest afterwards without fail.

Does it come up in a sale?

Increasingly, yes. Many buyers test during the inspection period, and an unmitigated high result becomes a negotiation. Several states require disclosure of known results. A $1,400 system installed before listing removes the conversation.

What if I have a crawl space?

A sealed membrane over the soil with depressurization underneath, $1,500 to $5,000. It also fixes the humidity problem most crawl spaces have, so it does two jobs.