Radon Mitigation Cost: $1,200 to $2,000 by Foundation (2026)

How much does radon mitigation cost

Published US prices. HomeGuide's and HomeAdvisor's averages differ by several hundred dollars, so both are shown. Your quote depends on the foundation, the number of suction points and where the pipe can run.

HomeGuide's 2026 national average is $1,600, with most jobs between $1,200 and $2,000. HomeAdvisor's June 2026 average is lower, at $1,028, with a typical range of $786 to $1,274. The Massachusetts Department of Public Health tells residents most systems cost $1,200 to $2,000. Massachusetts DPH says the price depends on home size, the foundations, any crawlspaces, the number of floors and how many suction points or fans the house needs. HomeGuide puts active soil depressurization at $2,500 and up for larger homes, and a dirt crawlspace that needs a membrane is priced higher still.

When to fix radon: the EPA action level

The EPA's action level is 4 pCi/L. At or above it, the EPA says fix the house. Between 2 and 4 pCi/L, the EPA says consider fixing it, and notes that getting below 2 is difficult. For scale, the average indoor level in the US is 1.3 pCi/L and outdoor air averages 0.4.

The reason for the line: the EPA estimates radon causes about 21,000 lung cancer deaths a year, about 2,900 of them in people who never smoked. That is a 2003 estimate with a wide uncertainty range of 8,000 to 45,000. It is the leading cause of lung cancer among non-smokers and the second leading cause overall. At 4 pCi/L over a lifetime, the EPA estimates about 7 in 1,000 never-smokers and about 62 in 1,000 smokers could get lung cancer.

How sub-slab depressurization works

Massachusetts DPH calls sub-slab depressurization the most common and usually the most reliable method. Suction pipes run through the slab into the crushed rock or soil below and connect to a radon vent fan. The fan runs all the time and keeps the soil under the house at lower pressure than the rooms above, so soil gas goes up the pipe instead of through cracks and gaps. The pipe discharges above the roof edge.

• Where the fan goes. In an unoccupied attic, a garage or outside the house, never in living space (UNR Extension).
• How long it takes. Most systems go in in less than a day (Massachusetts DPH).
• Sealing alone does not count. UNR Extension notes the EPA does not recommend sealing alone as a radon fix.
• The gauge. UNR Extension says a system needs an indicator that warns you if it stops working, and Massachusetts DPH's checklist includes a pressure gauge and a system label. Glance at the gauge now and then.
• Roof penetrations. If the pipe exits through the roof rather than up the outside wall, it is a new hole in the roof and has to be flashed like any vent. Roof flashing repair covers how vent boots fail.

Radon mitigation in a basement, slab or crawlspace

The foundation decides the method, and the method decides most of the price. UNR Extension says basements and slab homes usually get one of four kinds of active soil depressurization: sub-slab, drain tile, sump hole or block wall. Crawlspaces depend on the floor. UNR Extension adds that a house with mixed foundations may need a combination of methods.

Methods from University of Nevada, Reno Extension; prices from HomeGuide and HomeAdvisor. HomeGuide and HomeAdvisor both list crawl space encapsulation among their radon mitigation prices.

A dirt-floor crawlspace that is also damp or musty is two problems. If you already see mold on the joists, price mold remediation before a membrane goes down and the crawlspace is closed up.

Radon fan replacement and other costs over time

• Permit. $25 to $150 where one is required (HomeGuide, HomeAdvisor).
• The fan over time. HomeGuide says piping lasts 20 to 50 years or more but the fan may need repair or replacement after 5 to 10 years; HomeAdvisor gives the same 5 to 10 years. A typical fan warranty on a professional install is 5 years (HomeGuide).

Retesting after mitigation

A system is only done when a test says so. Massachusetts DPH says to test 24 hours to 30 days after installation, and if the system went in during warm weather, to test between November 1 and March 31. UNR Extension says no sooner than 24 hours after the fan starts. After that, retest every year or two.

The EPA's buyer and seller guide recommends that the retest be done by an independent tester. When the same company tests and mitigates, the EPA flags a possible conflict of interest, and some states require a waiver. HomeGuide suggests confirming the installation price includes the follow-up test. Massachusetts DPH's checklist asks the contractor to guarantee a result below 4 pCi/L, and ideally below 2.

Radon in home sales

Radon is often tested while a house is under contract, and the tester is very often the home inspector, according to the EPA. The EPA's real estate protocol is a short-term test of at least 48 hours, using two devices side by side, two back to back, or a continuous monitor, in the lowest level that could be used regularly. Windows and outside doors stay closed starting 12 hours before a test shorter than four days. If the average is 4 pCi/L or more, the EPA says fix the house.

• Buyers. If the seller has a test, the EPA says you can ask for a new one when it is not recent, for example older than two years.
• Sellers. A system already in place, with a retest result on paper, gives the buyer a number to work from. The EPA says most homes can be fixed for about the same cost as other common home repairs.
• Florida. State law (s. 404.056) requires a radon gas notice on at least one document at or before the contract for the sale or rental of any building (2020 statutes).
• New homes. The EPA says test a new home as soon as possible after moving in. Homes built with radon-resistant features have a 3 or 4 inch vent pipe already in place, and a fan can be added if the test is 4 pCi/L or more.

Buying a house with a solar array? Radon is one item on a longer list; buying a house with solar panels covers the rest of that checklist.

Radon mitigation near me: certification and state licensing

Look for a mitigator certified by the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB); both Massachusetts DPH and HomeGuide point to those two. Some states add their own rules on top:

• Florida. No one may do radon measurement or mitigation for a fee unless certified by the state, and they must work for a certified radon business (s. 404.056).
• Colorado. Radon measurement and mitigation tied to building or buying a home must be done by a state-licensed professional, and the state adopted AARST industry standards into law. DORA's Office of Radon Professionals keeps a searchable list of licensees.
• Other states. We did not confirm every state's rules for this page. The EPA's buyer guide says to check credentials with the state radon office. Ask the company for its certification number and the card's expiration date.

Questions to ask before you book

1. Are you NRPP or NRSB certified, and licensed or certified by the state where that applies?
2. Will you visit the house before giving a price? (Massachusetts DPH's checklist asks for a home visit before a bid.)
3. Where will the fan and the pipe go, and where will it discharge?
4. Does the price include a pressure gauge, a system label and the post-mitigation test?
5. What result do you guarantee, and what happens if the retest is above 4 pCi/L?
6. What is the fan warranty?

HomeGuide suggests getting at least three estimates and paying only a partial deposit before installation. Calls to the radon line go to an independent company that serves your area and takes this kind of job. How calls work. For other jobs around the house, see home repair costs or who to call.