Last updated 2026-08-20
TL;DR
Radon mitigation is the set of building changes that cut indoor radon, most often a fan that pulls soil gas from under a slab or membrane and vents it above the roof. You start by confirming state license rules, then taking an approved course and exam through NRPP, NRSB, or the state board. EPA treats 4 pCi/L as the action level. Do not advertise until the paper is in your name.
What is radon mitigation?
Radon mitigation is the work of changing a building so indoor radon drops and stays down. Most jobs run a fan and a pipe on a sealed suction point that pulls soil gas from under the slab or a crawl membrane and dumps it above the roof. That method is active soil depressurization. EPA treats 4 pCi/L as the number where you fix the house.[1]
That's the job. Not a gadget sale.
Radon is a radioactive gas from uranium in soil. It rides soil gas and collects in basements, crawl spaces, and under slabs. The 2016 EPA Citizen's Guide states, "EPA recommends fixing your home if the results of one long-term test or the average of two short-term tests show radon levels of 4 pCi/L or higher."[1] Outdoor air sits near 0.4 pCi/L. Congress set a long-term goal of getting indoor air that low. You will almost never hit outdoor levels with a residential fan system, and you should not promise that.
Mitigation is not testing. Testing gives you a number. Mitigation changes the pressure field and the entry paths. New people blur those two because the same customer asks for both. Keep the paper separate. Many states treat measurement and mitigation as different credentials.
You will also hear about sealing packages and heat recovery ventilators. Crawl encapsulation comes up constantly. Sealing alone is not a mitigation system. The 2016 EPA Consumer's Guide is blunt: "EPA does not recommend the use of sealing alone to reduce radon."[2] Ventilation can help in some buildings that need air changes. It is a second tool. It is not the first thing I would sell on a typical slab house.
EPA estimates about 21,000 radon-related lung cancer deaths each year in the United States.[3] CDC also treats radon as the second leading cause of lung cancer in the country.[13] That is why this trade exists. The work is simple in concept and easy to do badly.
How do you start radon mitigation?
You start radon mitigation on paper, not with a truck. Confirm whether your state licenses the work. Then take an approved mitigation course, sit the exam your state accepts (often NRPP or NRSB), and file the application the board actually uses. Do not bid a paid system until your name is on the credential that state wants.
That sequence sounds dull. It is how you stay legal.
Some states run their own license and do not treat a national card as enough. Florida Statute 404.056 puts radon certification in state law under the Department of Health.[5] Ohio licenses radon mitigation in Ohio Administrative Code Chapter 3701-69.[6] Kansas requires certification under the Radon Certification Law at K.S.A. 48-16a01 and the sections that follow.[7] Pennsylvania certifies radon businesses and individuals under 25 Pa. Code Chapter 240.[11] Hang an NRPP card on a van in a license state without the state paper and you can get fined.
If your state has no license, national certification is still the paper most buyers want. Realtors ask for it. So do many insurers. NRPP publishes a mitigation new-applicant path.[8] NRSB runs a parallel certification.[9] Confirm current course hours, exam fees, and application steps on those pages. Fees move. I will not invent them here.
Then get insurance and a written contract. Buy a standard you will actually follow. ANSI/AARST SGM-SF is the soil gas mitigation standard most serious shops use on existing homes.[10] Buy the standard. Read the diagnostic chapter twice.
A first job also needs a manometer and a diagnostic plan. Stock pipe and a fan you understand. Write a post-mitigation test plan before you cut the slab. Hire an independent tester when the state or the standard wants separation. Do not test your own work if the rule says you cannot.
State price pages such as radon mitigation cost in california or radon mitigation cost in florida will not replace the license check. They only tell you what buyers already pay. For a deeper paper walk-through after this, read the radon mitigation guide 101 new operators actually need.
If you want checklists in one binder, RadonPath sells a $149 one-time NRPP Mitigation Kit. Build your own folder if you prefer. The board still has to confirm you either way.
What radon level means you should mitigate?
You should mitigate when the accepted test result sits at or above the action level you and the client agreed to work toward. In the United States that number is 4 pCi/L under EPA guidance.[1] WHO set a recommended national reference level of 100 Bq/m3, about 2.7 pCi/L, in its Handbook on Indoor Radon.[4] Some buyers will ask you to chase 2.0 pCi/L. That is a contract choice. It is not a federal duty.
Short-term tests run about 2 to 7 days. Long-term tests run 90 days or more. EPA's fix recommendation can rest on one long-term result or the average of two short-term tests.[1] Closed-house conditions matter. A sloppy test sends you to install a system the house may not need, or lets you skip one it does.
I would not bid from a single 48-hour kit that sat on a kitchen shelf during a remodel. Ask how the test was done. If you cannot defend the number, retest.
The Surgeon General and EPA have told the public to test and fix homes since the 2005 Call to Action.[14] That does not make every 3.8 pCi/L kitchen kit a mitigation sale. Be honest when the data is thin.
Zone maps also get abused. EPA's Map of Radon Zones is a planning map, not a house test.[12] Zone 1 counties run higher on average. Plenty of Zone 3 houses still fail. Test the building. Then decide.
How does a radon mitigation system work?
A typical radon mitigation system lowers pressure under the slab or membrane so soil gas goes up the pipe instead of into the house. A fan on that pipe keeps the suction on. Exhaust leaves above the roof, away from windows and outdoor air intakes. You watch the system with a U-tube manometer on the riser.
Most residential work is active soil depressurization. You cut a suction pit and seal the slab hole. Then you run 3 inch or 4 inch PVC, mount the fan, and close major openings that short-circuit suction. Crawl homes get a heavy membrane with sealed seams. Suction sits under the plastic.
Pipe routing is where new techs get sloppy. Long horizontal runs show up fast. So do crushed fittings and attic fans with no condensate plan. I would learn one clean exterior riser detail before I offered hidden pipe as a premium. Add one attic detail after that.
Electrical is real work. Many cities want a permit and a disconnect. Do not steal power from a random receptacle and call it done.
Sealing helps the pressure field. It is not the system. Air purifiers do not remove radon gas. I would not sell one as mitigation. Heat recovery ventilators can dilute indoor radon in some houses. They cost more to run. They rarely beat a good ASD system on a slab.
Post-install, you measure vacuum at the riser. When you can, check communication across the slab. Then you schedule the radon retest. The fan curve and the manometer tell you the system is running. Only a test tells you the air is actually lower.
Do you need a license to do radon mitigation?
Yes, you need a license or certification if your state says you do, and you should assume you do until you prove otherwise. There is no single federal radon mitigation license. EPA points the public to state contacts and to national programs such as NRPP and NRSB.[15] The paper path is state first. The national card comes second.
Here is a simple comparison of places that actually wrote rules.
| Place | What you file | Rule to read |
|---|---|---|
| Florida | State radon certification | Fla. Stat. 404.056 [5] |
| Ohio | State mitigation license | OAC Chapter 3701-69 [6] |
| Kansas | State radon certification | K.S.A. 48-16a01 [7] |
| Pennsylvania | DEP radon certification | 25 Pa. Code Ch. 240 [11] |
| No-license state | National cert plus local permits | Confirm with the state radon office [12] |
Read the statute. Do not trust a Facebook group.
Some states split measurement and mitigation. Some certify the individual and the business as separate filings. Some want a responsible certified person on every job. Reciprocity is uneven. An Ohio card will not automatically open Florida.
If you work across a state line, check both boards before you bid. I would not take a weekend special in a license state on a buddy's number. That is how people lose the credential they just paid for.
Local building departments still want mechanical or electrical permits in a lot of cities even when the state has no radon license. Call the permit desk. Get the answer in writing if they waffle.
What paperwork do you need before the first install?
Before the first paid install you need the credential the state wants, proof of insurance, and a business identity the city recognizes. You also need a written scope the client can sign. Add the current mitigation standard you claim to follow. Add a plan for the post-mitigation test. If any of that is missing, you are not ready.
Course completion is not a license. The exam pass is not a license. The board letter is the paper that lets you advertise. In a no-license state, the national wallet card plays that market role.
Insurance is not optional if you want commercial work or realtor referrals. Ask the carrier for radon mitigation, not generic handyman. Confirm pollution or professional language. I cannot quote a premium that will still be true next month. Call two specialty brokers and compare.
Permits sit on a different desk. Some jurisdictions treat the fan as mechanical. Some want electrical for the disconnect. Some want nothing. Guess wrong and you redo a finished riser.
Keep a job file. Photos of the open slab help. So do shots of the suction point, the exhaust clearance, the manometer, and the labeled system. Those pictures save you when a buyer calls back in 18 months. Radon mitigation guide 103 for people entering the trade walks more of that field paper if you want it.
What training and exams do new mitigators take?
New mitigators take an approved mitigation course, then an exam from NRPP, NRSB, or the state board that runs its own test. After that they file an application with the ID, photos, and insurance that board lists this year. Confirm every hour count and fee on the current application page. I will not invent a number the board can change tomorrow.
NRPP's mitigation new-applicant page is the place to start if your state points at NRPP.[8] NRSB's certification page is the other national door.[9] Some states accept either. Some accept only their own class.
I would take the residential mitigation course first. Skip the fancy multifamily add-on until you have twenty slab houses behind you. The extra credential looks good on a website. It does not teach you how to cut a pit in wet clay.
CE hours come later. Do not buy three years of conference tickets in month one. Put that money into the SGM-SF standard. Then buy a decent micromanometer.
If a trainer will not tell you which states accept the course, pick another trainer. That is a basic question. The wrong answer costs you a second class.
Measurement training is a separate path. If you want to test and mitigate, you may need both courses. You may need both applications. Check the conflict rules on testing your own mitigation work before you pay twice.
What does first-year radon mitigation work actually look like?
First-year radon mitigation work is a few systems a month if you are lucky, plus unpaid callbacks. You will spend more time on permits and test reports than you expect. The field work is pipe and a fan on a clean suction point. The business is paper and insurance. And it is not overselling the number you can hit.
The 2016 EPA Consumer's Guide to Radon Reduction put the average radon mitigation cost at about $1,200, with a typical range of about $800 to about $1,500.[2] That figure is old. Labor and fans moved. Use it as a floor for the conversation, then check current local pages such as radon mitigation cost in colorado, radon mitigation cost in arizona, and radon mitigation cost in connecticut. Nobody publishes a clean national first-year P&L for this trade. Be wary of anyone who claims they do.
Materials on a simple slab can be a few hundred dollars. The rest is labor, drive time, and warranty risk. Add the independent retest. I would price the first twenty jobs to learn, not to get rich. Cheap work becomes free work when you have to add a second fan.
A used van beats a wrapped new truck. One fan family you stock in two sizes beats a wall of brands. A printed contract beats a text thread. That is the whole first-year kit, minus the credential.
Callbacks will happen. Budget a revisit rate. If your post-mitigation fail rate is high, your diagnostics are weak. Slow down. Measure communication. Do more than add a bigger fan and hope.
Which radon mitigation method should you learn first?
Learn active soil depressurization on slab houses first. It is the method EPA still treats as the usual residential approach, and it is the system most buyers already recognize.[2] After you can hit a stable vacuum and a passing retest on slabs, move to crawl membranes. Save block-wall suction and drain-tile tie-ins until the simple houses are boring. Large multifamily work can wait too.
I would not lead with sealing packages. I would not lead with air exchangers. Radon paint is not a primary offer. Those products have a place as helpers. They are a weak thing to sell first.
Sub-membrane depressurization is the crawl space version of ASD. The failure mode is a torn or unsealed liner. If you cannot detail a sump and a seam, do not book the crawl.
New construction is a different product. Passive rough-in comes first. A fan goes on later if the test fails. Codes and RRNC details vary. Do not treat a passive stack as a live mitigation system. It is a pipe until a fan and a test make it one.
Pick one exhaust detail that meets the clearance rules in SGM-SF and repeat it.[10] Custom art pipe is how water ends up in a fan.
How do you prove a radon mitigation system worked?
You prove a radon mitigation system worked with a post-mitigation radon test, not with a manometer photo. The manometer shows the fan is pulling. The test shows the indoor air dropped. EPA's public guidance still sends people back to test after a system goes in, and to test again about every two years.[1]
I would wait until the system has run long enough for the house to stabilize, then use a short-term test under the closed-house conditions the device and the standard require. When the state or the client wants independence, hire a measurement professional who is not you.
Write the before number and the after number into the job file. Add the device, the dates, and the system tag. If you guaranteed "below 4" or "below 2," that sentence now has to match the report. Do not guarantee outdoor air. You will lose.
A failed retest is not a moral event. It is a diagnostic event. Check power and fan rotation. Look for crushed pipe, open sumps, and slab openings you missed. Then fix and retest. Two extra hours here beat a bad review and a free second system.
For more of the first-year operating rhythm, radon mitigation guide 105 for first-year operators is the next read.
What is a waste of money in the first year?
A waste of money in year one is any credential, tool, or coach that does not get you a legal install and a passing retest. Dual national certifications in a state that only wants its own license are a waste. A wrapped truck before job ten is a waste. A thermal camera before you own a micromanometer is a waste.
Franchise fees in this trade rarely pay for themselves if you already know how to cut a pit. I would not buy a lead service that sells "EPA certified" language either. EPA does not certify mitigators.[15] Using that phrase is how you get a complaint.
Air purifiers sold as radon fixes are a waste for you and for the client. Same for most sealant-only packages billed as mitigation.[2]
Buy the standard. Buy insurance. Then buy one good diagnostic gauge. Stock two fan models you understand. Spend the rest on fuel and on doing the second visit when the first house fails. That list is not glamorous. It keeps you in business.
How do state rules change the radon mitigation path?
State rules change the radon mitigation path in practical ways. They decide if you need a license. They decide who may test the house after you finish. They also decide what you must put on the system label and the contract. The physics does not change much. The paper does.
A no-license state still has building permits and contractor registration. Consumer-protection law still applies. Do not read "no radon license" as "no rules." A heavy license state will check your course and your exam. It may also want insurance proof and an employee list. Reciprocity is a phone call, not a hope.
I would keep a one-page sheet per state you touch. Put the board name and the application URL on it. Note whether NRPP or NRSB counts. Note the permit habit in the cities you drive. Note the retest independence rule. Update it when the board changes a form. They will.
RadonPath is an independent publisher, not a law firm and not a mitigation company. Confirm every current fee, quota, and form with the board that will print your name. No article can promise approval or a processing time. If you want the kit path after you have read the rules, start at /start.
The real start is still boring. Read the statute. Take the class the board names. File the application. Then cut the first pit.
Frequently asked questions
What is radon mitigation?
Radon mitigation is the set of building changes that lower indoor radon and keep it down. Most homes get active soil depressurization: a fan and pipe pull soil gas from under a slab or crawl membrane and vent it above the roof. EPA uses 4 pCi/L as the usual fix point. Testing is a separate task and often a separate credential.
How do you start radon mitigation?
Start with the state board, not a truck. See if mitigation is licensed where you will work. Take the course that board accepts, pass NRPP, NRSB, or the state exam, then file the real application. Add insurance, a written contract, and the AARST SGM-SF standard. Do not advertise paid installs until the credential is in your name.
Is radon mitigation the same as radon testing?
No. Testing measures the indoor number. Mitigation changes how soil gas enters the building. Many states issue separate measurement and mitigation credentials, and some forbid you from testing your own mitigation work. Keep the reports, devices, and applications on different tracks even if the same customer wants both.
Can a homeowner install their own radon mitigation system?
Some states let an owner work on their own house and still restrict who may sell mitigation for hire. Other states are stricter about who may install a system at all. Confirm the rule with the state radon office before you advise a DIY path. A bad homeowner install still needs a real retest, and it can be expensive to redo.
How long does a typical radon mitigation install take?
A simple slab system is often one working day plus a later retest visit. Crawl membranes, block walls, and messy electrical or permit work run longer. Nobody publishes a solid national time study for this trade, so do not promise an afternoon on a house you have not seen. Walk it first.
Do you need both NRPP and a state radon license?
Only if the state wants both, which is uncommon. License states usually want their own card and may accept NRPP or NRSB coursework toward it. No-license states often treat a national certification as market paper. Paying for two national cards in a state that only honors its own license is a waste. Confirm with that board.
What is the EPA action level for radon?
EPA recommends fixing a home when one long-term test or the average of two short-term tests is 4 pCi/L or higher, per the 2016 Citizen's Guide to Radon. Outdoor air is about 0.4 pCi/L. WHO's handbook uses a 100 Bq/m3 reference level, about 2.7 pCi/L. Chasing 2.0 pCi/L is a contract choice, not a federal duty.
How soon should you retest after mitigation?
Retest after the system has run long enough for the house to stabilize, using the closed-house conditions the device and the standard require. EPA also tells occupants to test again about every two years after a system is in. When independence is required, hire a measurement pro who did not install the system.
Is sealing cracks enough to mitigate radon?
No. The 2016 EPA Consumer's Guide says EPA does not recommend sealing alone to reduce radon. Sealing helps an active soil depressurization system hold vacuum. Sold by itself, it is a weak primary method and a common way new operators underdeliver. If you sell sealing, sell it as a helper, not as the system.
What records should you keep on each mitigation job?
Keep the signed scope, the before test, diagnostic notes, photos of the suction point and exhaust, the system label, the manometer reading, permit numbers, and the post-mitigation test. Add fan model and install date. Those files answer realtor and buyer calls a year later. Some state boards also specify what must stay in the customer packet.
Can you start in measurement only and add mitigation later?
Yes, and it is a clean way in if your state splits the credentials. You learn how tests fail and how houses behave before you cut slabs. Check conflict rules first. Some boards limit testing your own mitigation work, so the second credential may not let you be the only person on a job.
Does EPA certify radon mitigators?
No. EPA does not certify or license radon mitigators. It sets public guidance, including the 4 pCi/L action level, and points people to state programs plus national bodies such as NRPP and NRSB. Advertising yourself as EPA certified is a complaint waiting to happen. Use the credential name the board actually issued.
What fan should a new mitigator stock first?
Stock one fan family you understand, in two capacities that cover most houses you will see. Learn the curve, the condensate behavior, and the noise complaint pattern on that family before you add brands. A wall of models looks like a shop. It usually means you do not know what you installed last month.
How do you get insurance for radon mitigation work?
Call specialty brokers and ask for radon mitigation coverage, not a generic handyman policy. Confirm whether they want your state license or national card first. Premiums change, so I will not invent one. Get the certificate language in writing before you bid realtor work. Some boards ask for proof on the application itself.
Sources
- U.S. EPA, A Citizen's Guide to Radon (2016): EPA recommends fixing a home if one long-term test or the average of two short-term tests is 4 pCi/L or higher; outdoor air is about 0.4 pCi/L; retest about every two years after mitigation.
- U.S. EPA, Consumer's Guide to Radon Reduction (2016): Average radon mitigation cost about $1,200 with a typical range of about $800 to about $1,500; EPA does not recommend sealing alone.
- U.S. EPA, Health Risk of Radon: EPA estimates about 21,000 radon-related lung cancer deaths each year in the United States.
- WHO Handbook on Indoor Radon (2009): WHO recommends a national reference level of 100 Bq/m3 (about 2.7 pCi/L) for indoor radon.
- Florida Statute 404.056 (2023): Florida wrote radon notification and personnel certification requirements into state statute under the Department of Health.
- Ohio Administrative Code Chapter 3701-69: Ohio licenses radon testing and mitigation in OAC Chapter 3701-69.
- Kansas Revisor of Statutes, K.S.A. 48-16a01: Kansas requires radon certification under the Radon Certification Law, K.S.A. 48-16a01 et seq.
- NRSB, Certification: NRSB operates a parallel national radon certification program for measurement and mitigation.
- ANSI/AARST SGM-SF-2023, Soil Gas Mitigation for Existing Homes: SGM-SF is the ANSI/AARST soil gas mitigation standard used for existing homes, including diagnostics and exhaust details.
- 25 Pa. Code Chapter 240, Radon Certification: Pennsylvania certifies radon individuals and businesses under 25 Pa. Code Chapter 240.
- U.S. EPA, EPA Map of Radon Zones: EPA's Map of Radon Zones is a county planning map, not a substitute for testing a specific building.
- CDC, About Radon: CDC identifies radon as the second leading cause of lung cancer in the United States.
- U.S. EPA, Find a radon test kit or measurement and mitigation professional: EPA does not certify mitigators and instead points the public to state contacts and national programs such as NRPP and NRSB.