Last updated 2026-08-20
TL;DR
Radon mitigation is the building work that lowers indoor radon, usually a fan and sealed pipe that pull soil gas from under a slab or crawl membrane and exhaust it above the roof. Start by reading your state's license or certification rule (EPA has no federal installer license), take the named course, pass the exam, then file the current board packet. EPA's action level is 4.0 pCi/L.
What is radon mitigation?
Radon mitigation is the building work that lowers indoor radon gas. In most houses that means a sealed pipe and an in-line fan that pull soil gas from under a slab or crawl membrane and exhaust it above the roof. Testers measure. Mitigators change the pressure field. That split matters more than any tool you own.
EPA states the health case in one line you will repeat to clients. "Radon is estimated to cause about 21,000 lung cancer deaths per year," according to EPA's 2003 Assessment of Risks from Radon in Homes (EPA 402-R-03-003). [1] You will not smell a leak. Uranium in soil decays to radium, then to radon, and the gas rides soil air into basements, slabs, and crawl spaces. [2]
A mitigation system is not a filter and it is not a new furnace. The common residential method is active soil depressurization. You cut a suction pit, run PVC, mount a fan, seal the large openings, and prove the living space dropped. EPA's consumer guide still treats that method as the one that works in most houses. [3]
People entering the trade mix up mitigation with measurement. Measurement is devices, protocols, and a report. Mitigation is cutting, sealing, electrical, roof flashing, and a written layout. Some states let one person hold both credentials. Some force a wall between the installer and the person who runs the closeout test. Confirm that wall with the board that takes the fee, not a group chat.
I would not put "mitigation" on an invoice for a liner or a sump lid unless it is part of a designed soil-gas system. Boards and home inspectors read those words. Inflated labels create complaint files. Keep the definition boring and accurate.
How do you start radon mitigation?
You start by confirming your state's rule (a license, a national card only, or almost nothing), taking the mitigation course that card names, passing the exam, then filing the application the board publishes this year. Do not buy a truck first. Do not order a pallet of fans. Paper, then tools.
There is no federal radon contractor license. EPA points the public to two private proficiency lists, the National Radon Proficiency Program and the National Radon Safety Board, and to state programs where those exist. [4] Congress set a national indoor goal, not a national installer badge. The Indoor Radon Abatement Act says the national long-term goal is "that the air within buildings in the United States should be as free of radon as the ambient air outside of buildings." [5]
Here is the order I would use. Read the statute and the current packet for the state where you will take money. If that state is silent, read the NRPP or NRSB mitigation requirements and call the city permit desk. Sit the course the credential names. Pass the exam. Buy the insurance the form asks for. Then price a used core drill and a manometer.
State paper is not one story. Florida writes radon duties into section 404.056, Florida Statutes. [6] Ohio forbids paid radon testing or mitigation without a state license. [9] Kansas has a radon certification law. [8] Other states ask for little more than a business registration. Treat a national card as a private-program product, not a federal permit.
If you want those forms explained in one stack, RadonPath sells a $149 one-time NRPP Mitigation Kit. The kit does not replace the board. You still file what the board named this year, and you still confirm the fee on that board's page.
What radon level means a house should be mitigated?
EPA's action level is 4.0 picocuries per liter. Fix the house at or above that number, and consider a fix between 2 and 4. Outdoor air is about 0.4 pCi/L. [2] That is the number most real estate contracts still use.
WHO recommended a national reference level of 100 Bq/m3, about 2.7 pCi/L. [10] Those two figures confuse new operators. You will get calls from people who read the WHO page and want 2.7. You will get deals that treat 3.9 as a pass. Write the protocol on the report. Do not argue physics on the porch.
| Number | What it is | Who published it |
|---|---|---|
| 4.0 pCi/L | Action level to fix a home | U.S. EPA Citizen's Guide [2] |
| 2.7 pCi/L | 100 Bq/m3 reference level | WHO radon fact sheet [10] |
| 0.4 pCi/L | Typical outdoor air | U.S. EPA Citizen's Guide [2] |
| Outdoor equivalent | National long-term indoor goal | 15 U.S.C. 2661 [5] |
The National Academy of Sciences BEIR VI report is the risk backbone EPA still cites for homes. [11] Nobody has a perfect local risk number for one address. The closest honest line is EPA's national death estimate plus the 4.0 action level. [1][2]
I mitigate at 4.0 when the client hired me to meet the EPA number. I will also bid a 3.2 house if the purchase contract asked for it. I will not promise zero. Outdoor air is not zero. The federal goal is outdoor-equivalent, not a "radon free" sticker. [5]
After the fan runs, you want a clear drop and a number under the target the contract named. If a standard system cannot get under 4.0, stop guessing. Add suction or find the leak. Do not average a bad continuous-monitor trace into a pass.
How does a typical radon mitigation system work?
A typical house system is active soil depressurization. You create a low-pressure field under the slab or membrane so soil gas goes into the pipe instead of the living space. A fan in the attic or on an exterior wall holds that field. Exhaust leaves above the roof eave, away from windows. [3]
Crawl houses get a sealed membrane with suction under the plastic. Block-wall houses sometimes need hollow-block suction. Mixed foundations eat hours. That is where new operators lose money, not on the easy ranch with one pit.
Diagnostic work is a smoke pencil, a micromanometer, and a walk of the slab for big holes. I would not skip a communication test on a large or cut-up slab. One pit in a tight pour can fail the far corner. EPA's consumer guide describes the families of systems. Serious shops then build to the ANSI/AARST soil-gas mitigation standard the course named. [3][4]
Electrical is where cheap jobs get ugly. Fans need a disconnect, the right gauge, and a location you can service. Condensate in cold attics kills fans. A U-tube manometer is not a decoration. It is how the homeowner sees that the fan is pulling.
Sealing is not optional cosmetics. Open sumps, utility penetrations, and an unused pipe boot will wreck a pressure field. Seal the big holes. Do not foam every hairline crack for two extra days. Diminishing returns show up fast. Take photos before you close the walls.
Do you need a license to do radon mitigation?
Sometimes yes, sometimes no. EPA does not issue a contractor license. Several states do. If you take money in a license state without the card, you have a legal problem, not a marketing problem. [4]
Kansas certifies people under its radon certification law. Florida puts radon programs and related duties in section 404.056, Florida Statutes. Ohio Revised Code 3723.02 says no person shall provide a radon testing or mitigation service without a license. [6][8][9]
If your state has no radon board, you still have the electrical code, the mechanical code, any general contractor rule, and the city permit desk. A national NRPP or NRSB mitigation credential helps you get on the lists EPA points to. It is not a substitute for a state card where the statute requires one. [4]
Confirm the current application, fee, and insurance line with the board. Those numbers move. I will not quote a fee here because a stale fee is how people bounce an application.
Renewal is its own calendar. If you already work in a license state, read that state's renewal rules before you treat continuing education as optional. Start with radon mitigation renewal in Florida, radon mitigation renewal in California, or radon mitigation renewal in Arizona if those are on your map.
What training do you take before you hang a fan?
Take the mitigation course the credentialing body names, then sit that exam. For a national mitigation card that means an approved entry course plus the exam NRPP or NRSB lists. License states often accept those exams or run their own. EPA's professional page is the public pointer to both lists. [4]
A weekend course will not teach you a wet basement in January. It will teach vocabulary, device types, and the standard the exam was written against. That is enough to sit the test. It is not enough to price a four-foundation farmhouse.
I would not stack six extra certificates in month one. Measurement plus mitigation is enough if your state allows both. Adding mold, lead, and infrared because a coach said so burns cash. Get real days under someone who already holds the card if you can. Paid ride-alongs beat another plaque.
Radon-resistant new construction is a different skill. EPA publishes the basics for builders: gravel, plastic, a vent pipe, and a jack ready for a fan. [13] New-home rough-in work is nice revenue. It is not the same as diagnosing a 1952 block basement.
Waste of money: a pricey "accelerator" that reprints EPA PDFs you can download free. Read the Citizen's Guide and the Consumer's Guide yourself before you pay anyone to summarize them. [2][3]
What paper do first-year mitigators actually file?
You file whatever the state packet and the local permit desk named, plus the records the mitigation standard says to leave with the homeowner. A typical stack is an application, proof of the course and exam, a photo, a bond or insurance page, and later a permit for the electrical or the system. Confirm each line. Do not copy a packet from 2019.
System records I would keep even if the board is sleepy: the pre-mitigation test (who ran it, device, start and stop), a floor plan with suction points, fan model and serial, the pressure reading at the U-tube, electrical notes, photos of the roof jack and the sealed sump, and the post-mitigation test. When a buyer complains three years later, that folder is the job.
Some states require an independent post-test. Some let you test your own work. Florida real estate culture cares about the written radon language in 404.056. [6] Kansas and Ohio care that the person on site was certified or licensed. [8][9]
City permits vary by the week and by the inspector. Call the building department with the address. Ask if they want a mechanical permit, an electrical permit, or a radon permit. Then do that. Arguing that EPA does not require a permit is how you get a stop-work tag.
If you work across state lines, you do not get to pick the easier state's rules. You follow the state where the house sits. Renewal clocks sit in that state too. See radon mitigation renewal in Colorado and radon mitigation renewal in Connecticut if those desks are on your list.
How much does radon mitigation cost a homeowner?
EPA's 2016 Consumer's Guide to Radon Reduction said the average radon reduction system costs about $1,200, with a range of about $800 to about $1,500. [3] That is a 2016 national pamphlet number, not your bid on a 2026 crawl in the mountains. Labor, roof pitch, and liners have moved since then. Use EPA's range as the public's anchor, then price the house in front of you.
A simple slab ranch with a good pit and an attic fan can still land near that pamphlet if your overhead is sane. A big crawl with a full membrane, or a house with three foundation types, will not. I would rather lose a bid than install a one-pit toy on a split that fails the post-test.
Do not sell a 10 year fan promise you cannot honor. Fans fail. Budget a replacement path. A service plan is fine if you actually show up.
For your own first-year cost, the expensive mistakes are a new wrap on the truck, a booth at every home show, and inventorying 30 fans for a discount. Buy two fans you understand, a drill that survives, and a calibrated manometer. Confirm any state application fee with the board. I will not invent that number.
What standard should you follow on the job?
Follow the mitigation standard your course, your state, and your credential named. In practice that is usually the ANSI/AARST soil-gas mitigation standard for existing homes, plus the electrical and mechanical code the inspector uses. EPA's consumer guide is for homeowners. It is not your install spec. [3][4]
The Indoor Radon Abatement Act set a national goal, not a pipe diameter. [5] Details live in the standard: discharge height, labeling, fan location, and what you leave the homeowner. If your state adopted a specific edition, that edition wins. Confirm the edition. Do not guess from memory.
I would not mix random video details into a system you will sign. Inspectors and opposing experts read the named standard. Your photos should match that document. If you cannot point to a clause, do not install the detail.
New construction rough-ins should follow EPA's radon-resistant new construction basics and whatever builder standard your code official named. [13] A capped tee in a wall with no gravel and no membrane is not a system. Do not certify a dummy pipe just to close a new-home checklist.
What should you buy first, and what is a waste?
Buy the credential path, the insurance the board named, a core drill, a vacuum, PVC, a manometer, smoke, and one fan family you can get parts for. That is the starter kit. Everything else waits.
A thermal camera is a toy in month one. A second pickup is a toy. A franchise that wants a cut of every job for leads is a toy unless you cannot get a phone to ring any other way. Read the free EPA guides before you pay for a reprint. [1][2][3]
Paid coaching can be worth it if the person still installs. Ask for job addresses, not a slide deck. If they will not show a recent system, keep your checkbook closed.
I keep a small stock because fans sit in warehouses until they do not. Two backup fans, not a pallet. Same rule for pipe fittings. Running to the supply house mid-job is cheaper than owning a garage you cannot walk through.
CDC and EPA both tell the public to test and to fix high homes. [2][14] Your job is the fix. Spend money on the tools that make the fix hold, not on a logo package.
How does post-mitigation testing work?
You prove the house dropped. A short-term test after the system has run (often a day of operation, then a two-day test, depending on the protocol) is the common residential closeout. Some states require a listed measurement professional who is not you. Confirm that split. [4]
EPA still tells homeowners to test after a system goes in and to test again later. [2][3] Put that in the packet you leave on the counter. Include the fan warning. If the U-tube is flat, call.
Do not help a failing post-test by moving the device to a third-floor bedroom. That is how you lose the credential. If the number is high, add suction or find the leak. Write what you did.
CDC and EPA have asked the public to test homes and to fix high ones. [14][2] Your closeout test is how that request becomes a file, not a speech. Keep the device report with the fan serial. Future you will need both.
What does a first year in this trade actually look like?
Year one is a few real installs, callbacks on the first five, and a paper habit. You will underbid mixed foundations. You will overbuy pipe. You will wait on a city inspector who has never seen a radon fan. None of that means you picked the wrong trade. It means you should have bid the hard house slower.
Read one longer operator guide after this page. The radon mitigation guide new operators actually need is the next click if you already want the trade, not the definition.
Keep continuing-education dates on a paper calendar. States do not share a clock. If you hold radon mitigation renewal in Georgia or radon mitigation renewal in Idaho on your list, set the reminder the day the card arrives. Boards do not care that you were busy.
RadonPath is an independent publisher, not a law firm and not a mitigation company. If you want the forms stack in one kit, that kit is on /start. Confirm every fee and form with the board that will stamp you. Nobody here can promise an approval date.
Frequently asked questions
What is radon mitigation?
Radon mitigation is the building work that lowers indoor radon, usually active soil depressurization. A fan and sealed pipe pull soil gas from under a slab or crawl membrane and exhaust it above the roof. It is not a filter and it is not a measurement report. Testers measure. Mitigators change the pressure field and then prove the living space dropped.
How do you start radon mitigation?
Read the state rule where you will take money, take the mitigation course that rule or NRPP or NRSB names, pass the exam, then file the current board packet and any city permit. EPA has no federal installer license. Confirm fees with the board. Buy tools after the paper path is real, not before.
Does EPA license radon contractors?
No. EPA does not issue a radon contractor license. It points the public to NRPP and NRSB lists and to state programs. Congress set an indoor radon goal in 15 U.S.C. 2661. It did not create a national installer badge. If your state licenses the work, that state card is the one that matters.
What is the EPA action level for radon?
EPA's action level is 4.0 pCi/L. The Citizen's Guide says to fix homes at or above that level and to consider a fix between 2 and 4. Typical outdoor air is about 0.4 pCi/L. WHO's 100 Bq/m3 reference is about 2.7 pCi/L. Write which target the contract used.
Can I mitigate radon without a license?
Only if your state and city do not require one. Ohio, Kansas, and Florida are examples of states with statutory radon programs. A national NRPP or NRSB card is not a substitute where a statute requires a license. Confirm the current rule with the board before you take a deposit.
Is DIY radon mitigation legal?
Homeowners can often work on their own house, but paid work is different. License states regulate people who take compensation. Even a homeowner still has electrical code and permit rules. I would not tell a new operator to coach DIY installs. If you take money, follow the paid-work statute.
What is active soil depressurization?
Active soil depressurization is the usual residential method. You create suction under the slab or a crawl membrane so soil gas enters a pipe instead of the house. A continuously running fan holds that field and dumps the gas above the roof. EPA's consumer guide treats it as the method that works in most homes.
Do I need a measurement credential too?
You need whatever your state requires for the closeout test. Some programs let a mitigator test their own work. Others require an independent listed tester. Even where you may test, a separate measurement credential helps on real estate jobs. Confirm the wall between install and test with the board.
How much does a radon system cost?
EPA's 2016 Consumer's Guide put the average at about $1,200, with a range of about $800 to about $1,500. That pamphlet is still the public's anchor. Mixed foundations, full crawl liners, and steep roofs bid higher. Price the house, not the pamphlet, and do not promise the 2016 average on a hard crawl.
Can you mitigate a crawl space?
Yes. The usual approach is a sealed membrane with suction under the plastic, plus the same roof discharge you use on a slab. Leaks at piers, dirt walls, and plumbing penetrations kill the field. Crawl jobs take longer than a one-pit ranch. Bid the liner and the sealing, more than the fan.
How long does a mitigation install take?
A simple slab ranch can be a day for a practiced crew. Mixed foundations, full crawls, and permit waits are not a day. Nobody has a clean national time study I trust. The closest honest answer is: the fan is the short part, and the slab communication plus sealing is the long part.
How often do you renew a mitigation credential?
On the cycle the board or the national program printed on your card. It is not one national date. Set a reminder the day the card arrives. State renewal rules differ, so read the packet for the state where the house sits rather than copying a friend's calendar from another state.
Is NRPP the same as a state license?
No. NRPP is a private proficiency program. EPA points consumers to NRPP and NRSB. A state license is a government permission to take money. Some states accept the national exam toward their license. Some ignore it. You may need both. Confirm with the state packet, not the national brochure.
Who pays for the post-mitigation test?
The contract decides. Many mitigators include a closeout test. Some states require an independent tester, which is a separate invoice. EPA tells homeowners to test after the system goes in and to test again later. Put that in writing so the buyer does not think one two-day test lasts forever.
Sources
- U.S. EPA, Health Risk of Radon: EPA estimates about 21,000 U.S. lung cancer deaths per year from radon (EPA 402-R-03-003).
- U.S. EPA, A Citizen's Guide to Radon (2016 PDF): EPA action level is 4.0 pCi/L; outdoor air is about 0.4 pCi/L; test after mitigation.
- U.S. EPA, Consumer's Guide to Radon Reduction (2016 PDF): Average radon reduction system about $1,200, range about $800 to about $1,500; ASD is the usual method.
- U.S. EPA, Find a Radon Test Kit or Measurement and Mitigation Professional: EPA points the public to NRPP and NRSB listed professionals and to state programs.
- 15 U.S.C. § 2661, Indoor Radon Abatement Act national goal: National long-term goal is indoor air as free of radon as outdoor ambient air.
- Florida Statutes § 404.056 (2023): Florida statute 404.056 sets environmental radiation and radon program duties, including radon disclosure language.
- Kansas Statutes, Radon Certification Law, K.S.A. 48-16a01: Kansas has a statutory radon certification law for radon services.
- Ohio Revised Code § 3723.02: Ohio requires a license before a person provides a radon testing or mitigation service.
- World Health Organization, Radon and health fact sheet: WHO recommended a national reference level of 100 Bq/m3 (about 2.7 pCi/L).
- National Academy of Sciences, BEIR VI, Health Effects of Exposure to Radon: BEIR VI is the National Academy risk assessment EPA cites for residential radon.
- U.S. EPA, Radon-Resistant New Construction: EPA publishes radon-resistant new construction basics: gravel, plastic, a vent pipe, and a jack ready for a fan.
- CDC, Protect Your Home from Radon: CDC advises the public to test homes for radon and to fix high levels.