Last updated 2026-08-19
TL;DR
Radon mitigation is the job of cutting indoor radon, usually with a fan that pulls soil gas from under the house and dumps it above the roof. You start with an approved course, pass a national exam, then check whether your state adds its own license. EPA treats 4 pCi/L as the action level. Installed systems run $800 to $2,500. Never skip diagnostics or the post-mitigation test.
What is radon mitigation?
Radon mitigation is the building work that lowers indoor radon. In most houses that means a fan and pipe that pull soil gas from under a slab or membrane and dump it above the roof. You are changing pressure under the house so radon does not come in. You are not scrubbing room air.
EPA puts the hazard in plain language in A Citizen's Guide to Radon: "Radon is a radioactive gas. It comes from the natural decay of uranium that is found in nearly all soils." [2] The gas moves through cracks, sumps, and dirt crawl spaces. Once it is inside, it decays, and those decay products damage lung tissue.
The health case is not subtle. EPA attributes about 21,000 U.S. lung cancer deaths a year to radon. [1] WHO says, "Radon is the most important cause of lung cancer after smoking." [7] That is why this trade exists.
A mitigation job is a construction job with a number attached. The number is the post-mitigation radon result. If you cannot get a reliable number down, you did not finish.
People mix this up with air cleaning. A room filter is not radon mitigation. Crack sealing alone is not mitigation either. EPA's Consumer's Guide to Radon Reduction treats sealing as a helper, not the system. [3]
Stacking this work against other house trades? Read radon mitigation vs nearby career. The closest cousins are HVAC and waterproofing. The paper load sits closer to a licensed specialty.
How do you start radon mitigation?
You start on paper, not in a basement. Take an approved radon mitigation course, sit the national exam, get the credential, then ask your state radon office whether that credential is enough or whether you also need a state license. Then buy diagnostics gear. Then do practice houses. Then take paid work.
That order matters. Plenty of people reverse it. They buy a fan, cut a hole, and hope the number drops. That is how you earn callbacks, angry real estate agents, and in some states a fine.
National certification runs through NRPP or NRSB. NRPP publishes a Mitigation Specialist track with training and an exam. [11] Confirm current course lists, exam windows, and application steps on the certifying body's own pages. I will not quote a fee or a wait time here because those move.
State overlays are the part national blogs skip. Iowa writes mitigation rules in Iowa Administrative Code 641 Chapter 43. [12] Ohio writes them in Ohio Administrative Code Chapter 3701-69. [13] Some states have no radon license at all. You still owe the building official a legal vent and a legal electrical hookup.
After the card is in your wallet, start with diagnostics. Learn to run a micromanometer. Learn to find communication under a slab. Read ANSI/AARST SGM-SF before you bid a hard house. [10] EPA points to those consensus standards as the current practice documents. [9]
Want a walk-through of the early forms? radon mitigation guide 12 stays on the paper, not the sales pitch.
What radon number means you should fix the house?
EPA recommends fixing a home if one long-term test or the average of two short-term tests is 4 pCi/L or higher. [2][4] That 4 pCi/L figure is the U.S. action level, not a safe or unsafe cliff.
EPA also says to consider a fix between 2 and 4 pCi/L. [2][4] WHO recommends a national reference level of 100 Bq/m3, which is about 2.7 pCi/L. [7] Those two numbers trip up new techs. Use the number your client, your state, and the contract named. In U.S. real estate work, 4 pCi/L still drives most purchase agreements.
| Number | What it means | Source |
|---|---|---|
| 4 pCi/L | U.S. action level, fix the house | EPA Citizen's Guide [2] |
| 2 to 4 pCi/L | Consider a fix | EPA [2][4] |
| 100 Bq/m3 (~2.7 pCi/L) | WHO national reference level | WHO fact sheet [7] |
| $800 to $2,500 | Typical install cost band in the last EPA guide | EPA Consumer's Guide [3] |
A single short-term test swings with weather and how people live in the house. That is why EPA wrote the long-term versus two-short-term language. [2] Do not tell a buyer that 3.8 pCi/L means the house is fine forever. Houses change. Fans die.
NCI states that radon exposure carries lung cancer risk, and the risk rises with higher levels and longer time in the building. [6] ATSDR's radon materials match that no-threshold framing. [5]
Asked what I would do in my own house? I mitigate at 4 and I look hard at anything stuck over 2 if the house is easy. I would not spend the top of the EPA cost band chasing 1.2 pCi/L on a leaky old farmhouse. The fan still runs all day. Power is not free.
How does a typical home radon mitigation system work?
Most homes get active soil depressurization. You open a suction point through the slab (or you seal a crawl membrane), you pipe that point to an in-line fan, and you discharge above the roof. The fan runs all the time. A U-tube or digital manometer on the pipe shows that suction is present.
EPA's Consumer's Guide to Radon Reduction walks homeowners through this layout. [3] Minnesota Department of Health describes the same parts: pipe, fan, discharge, and a way to see that the system is working. [14]
Crawl spaces are not the same job as a poured basement. You usually lay a sealed membrane and suck from under it. Block-wall houses can need wall suction. Slab-on-grade ranches can have terrible pit communication. That is why you measure. You do not guess.
Electrical work has to meet the local code. Outdoor fans need a disconnect. Indoor fans need a proper rating for the space. I would not hang a cheap no-name fan in a conditioned attic and call it done. Fan choice is one of the few places cheap gear actually bites you inside a year.
Discharge location is not a vibe. Keep it away from windows and openings so you do not pull the same gas back in. SGM-SF spells out clearances. [10] Read them. Do not copy the last guy's roof jack if his pipe sits next to a dormer window.
Do you need a state license for radon mitigation?
Sometimes. There is no single federal radon mitigation license. EPA does not issue one. Your state might.
Iowa requires compliance with IAC 641 Chapter 43 for radon mitigation. [12] Ohio licenses radon mitigation specialists under OAC 3701-69. [13] Other states require a credential, a notice, or nothing beyond a business license and the electrical code. EPA tells the public to use qualified professionals and to check the state contact list. [8]
I treat national certification as the floor, not the ceiling. Cross a state line and you can be legal on Monday and illegal on Tuesday. Confirm with the board that prints the card. Do not trust a Facebook group roster.
Building permits are a separate question. Plenty of cities want a mechanical or electrical permit for the fan circuit even when the state has no radon license. Call the building department before you cut. It is boring. It is also how you stay on the job.
Someone offers to pull the permit under their license while you swing the hammer? Read your state chapter first. Several programs treat unlicensed mitigation as a violation even when a cardholder signs the report.
More state-shaped paper sits in radon mitigation guide 18 and radon mitigation guide 24.
What training and exams do new mitigators take?
You take a mitigation course that NRPP or NRSB accepts, then you sit that body's exam. NRPP's Mitigation Specialist page is the place to confirm current entry requirements. [11] I will not invent a sitting fee or a pass score here. Those belong on the certifier's site the week you apply.
The useful part of the course is not the decay-chain slideshow. It is pit communication, fan curves, crawl membranes, and how to fail a house on purpose during diagnostics so you know where the pipe has to go. If your course skipped hands-on manometer work, rent a house and practice.
Measurement is a different credential. If you want to test and mitigate, many states split those roles or bar you from testing your own mitigation work. Read that rule twice. Independent post-mitigation testing exists for a reason.
AARST's SGM-SF is the document I would actually study after class. [10] EPA's standards-of-practice page points practitioners at those consensus standards rather than at the old 1990s EPA manuals as the living rulebook. [9] Know which document your state adopted. Some still cite older EPA text in their code.
Classroom hours are not a personality test. Show up. Take notes on the diagnostic labs. Skip the merch table.
What paper do you collect before the first paid job?
Collect the national certificate, any state license or registration, your business registration, general liability insurance, and the local permit process. Add a written contract that names the pre-test result, the method, and how you will handle a fail. Add a one-page system diagram.
| Item | Who issues it | Confirm where |
|---|---|---|
| National mitigation credential | NRPP or NRSB | The certifier's current applicant page [11] |
| State mitigation license | State radon program, if the state has one | The numbered state chapter [12][13] |
| Local permit | City or county building department | The permit counter |
| Independent post-test | A listed tester, often not you | State rule plus the contract |
Selling in real estate transactions? Add whatever disclosure your state wants on the mitigation report. Iowa and Ohio both treat reporting and credential display as part of the program, not as optional stationery. [12][13]
I would not take a check until the contract says who pays for a redesign if the first pit does not communicate. That one clause saves friendships.
Keep the pre-mitigation test report in the job file. Keep photos of the suction pit, the cracks you actually sealed, the discharge, and the manometer. Keep the post-test. Boards and home inspectors ask for this stuff years later.
Forms vary. Confirm the current application, renewal, and report templates with the board. Nobody has a clean national packet that matches every state. If you want a kit that organizes the NRPP-oriented paper, the RadonPath $149 one-time NRPP Mitigation Kit is at /start. You can also build the same file from the board PDFs for free.
See radon mitigation guide 30 for a tighter list of what belongs in the job jacket.
What does first-year radon mitigation work look like?
First-year work is mostly straightforward basements and a few crawl spaces that teach you humility. Real estate deadlines will run your calendar. Winter is busy in cold states because tests spike and closings still happen.
You will underbid communication problems. Everyone does. A slab with poor aggregate under it can eat a whole day. I would rather lose a bid than promise a one-pit system on a house I have not measured.
Cash flow is lumpy. Fans and PVC are cheap next to labor. The expensive mistakes are return trips and a failed post-test on a closing morning. Price the diagnostic hour. Do not give it away.
You will also spend time explaining that the system runs forever. Clients pull the plug to save a few dollars a month. Then the next test is 9 pCi/L and they call you a crook. Put "fan runs continuously" on the invoice in plain type.
Still weighing the nearby trades? radon mitigation vs nearby career is the honest comparison. Waterproofing companies sometimes bolt on radon. Some do it well. Some treat the pipe as a decorative upsell.
radon mitigation guide 36 helps once you have a few jobs and the paperwork starts to drift.
How much does a home radon mitigation system cost?
EPA's Consumer's Guide to Radon Reduction says a typical mitigation system installation costs between $800 and $2,500. [3] That range is from the 2016 guide. Labor and fan prices have moved since 2016, so treat it as the last federal published band, not this week's bid sheet.
Simple basement, good pit communication, outdoor fan, short roof run: you land near the bottom if your overhead is low. Big footprint, multiple suction points, finished ceilings, a long interior chase, or a wet crawl: you leave the EPA band.
I would not use $800 as a marketing hook. You will skip diagnostics to hit it. That is how systems get installed on the wrong side of a footing.
Homeowner DIY kits exist. Some work on easy slabs. Many miss SGM-SF clearances or electrical code. [10] If a client wants to DIY, I would rather they buy a good fan and hire you for diagnostics than the reverse.
Operating cost is a fan that draws tens of watts, all year. Nobody has a single national kWh figure that fits every fan and every utility. Tell clients to read the fan wattage and do their own math.
More bid-sheet detail lives in radon mitigation guide 42.
Which standards apply to the work itself?
The living practice standard for existing homes is ANSI/AARST SGM-SF (Soil Gas Mitigation Standards for Existing Homes). The 2023 edition is the current named publication. [10] EPA's radon standards of practice page directs people to these consensus standards. [9]
Your state may adopt SGM-SF by name, adopt an older EPA mitigation standard, or write its own chapter. Iowa and Ohio both write operational duties into administrative code on top of any national standard. [12][13]
SGM-SF is where pipe size, fan siting, labeling, and discharge height stop being opinions. If you argue with a home inspector, argue from the standard, not from "this is how we do it in this county."
Measurement standards are separate. Do not use a junk charcoal kit from a hardware aisle as your official post-test if the contract or the state wants a listed device and a certified tester.
I still keep a copy of EPA's Consumer's Guide in the truck. [3] Clients understand it. Then I work to SGM-SF.
What first-year spending is a waste of money?
A full truck wrap before you have a license is a waste. A $4,000 camera kit for year one is a waste. A franchise pitch that sells you leads instead of diagnostics skill is usually a waste.
Spend money on a decent micromanometer, a shop vac you can dedicate to pit excavation, the right core bit, and a fan line you can warranty. Spend money on the course and the state card. Spend money on liability insurance that actually names radon mitigation.
I would not buy a close-rate script. This is not solar. The house either has a number or it does not.
Another waste: cheap fans with no replacement path. When that fan dies in month 11, you own the callback.
Do not pay for national directory listings that are just scraped NRPP names. EPA already tells the public how to find qualified people. [8]
radon mitigation guide 48 is a reasonable next read if you are building a year-one budget.
How do you confirm board rules in your state?
Call or email the state radon program, then read the chapter they cite. EPA's professional finder page is the jump-off for state contacts. [8] Then open the actual code. Iowa's rules live in IAC 641.43. [12] Ohio's live in OAC 3701-69. [13] Other states publish a statute, a regulation, or only a guidance page. If you cannot name the chapter, you do not know the rule.
Confirm application forms, renewal cycles, continuing education, and any ban on testing your own systems with that board. I will not guess processing time. Boards change staff. Websites lag.
When two sources disagree, the regulation wins. A trainer's slide deck is not the law.
RadonPath is an independent publisher, not a law firm and not a service company. Use this as a map, then confirm every form and fee with the board that issues your card.
Frequently asked questions
What is radon mitigation?
Radon mitigation is the building work that lowers indoor radon, usually by pulling soil gas from under a slab or crawl membrane and venting it above the roof. You change pressure so radon does not enter. You do not filter room air. EPA's Consumer's Guide to Radon Reduction is the public walkthrough of the common layouts.
How do you start radon mitigation?
Take an approved mitigation course, pass a national exam (NRPP or NRSB), then ask your state radon office if you also need a state license. Get insurance and learn the local permit desk. Buy a micromanometer before you buy marketing. Confirm every current form and fee with the board. Do not start by drilling a random hole.
Is radon mitigation the same as radon testing?
No. Testing measures the number. Mitigation changes the building so the number drops. They are different credentials in most programs. Many states restrict you from running the official post-test on your own mitigation job. Read that split before you print business cards that say you do both.
Can a homeowner install their own radon mitigation system?
Some do, and an easy basement can cooperate. Clearances, electrical code, and SGM-SF details are where DIY jobs fail. A few states also limit who may offer mitigation for pay. If a homeowner wants to DIY, paid diagnostics plus a listed fan beat a blind core hole. Confirm any permit first.
How long does a radon mitigation system have to run?
All the time. The fan is not seasonal. If someone unplugs it to save a few dollars a month, radon can climb again. Put continuous operation on the invoice. Tell clients a dead fan is a failed system, not a cosmetic issue. Retest after any long outage.
Do you need a post-mitigation radon test?
Yes. The job is not done until a listed test shows the number came down. EPA's fix language is built around test results, not around the presence of a pipe. In many states the post-test should be independent of the installer. Put that expectation in the contract before you start.
Is NRPP certification enough in every state?
No. NRPP is a national credential, not a federal license. Iowa, Ohio, and several other states add their own chapters, cards, or reporting rules. Some states have no radon license. EPA tells people to check state contacts. Confirm with the program that actually prints your card before you bid across a state line.
What is the difference between NRPP and NRSB?
They are the two national radon credentialing bodies. Either can be the floor for training and an exam. Your state may accept one, both, or neither without an extra state license. I would pick the body your state program names in writing. Confirm current tracks on each organization's applicant pages, not on a reseller blog.
Does mitigation take radon to zero?
No. You are lowering the entry of soil gas, not erasing uranium in the dirt. EPA's action level is 4 pCi/L, and EPA still says to consider work between 2 and 4. Outdoor air is not zero either. Promise a target in the contract, not a magic zero.
What if the first system stays above 4 pCi/L?
You diagnose again. Add suction, fix leaks in the slab or membrane, check the fan, and look for re-entrainment at the discharge. This is why the contract should say who pays for a second pit. A failed post-test is a design problem until proven otherwise, not a client attitude problem.
Can you mitigate a crawl space like a basement?
Not with the same details. Crawl work is usually a sealed membrane with suction under it, plus careful sealing at piers and walls. A bare-dirt crawl with a pipe stuck in one corner is a common fail. SGM-SF and EPA's consumer guide both treat crawl layouts as their own method, not as a short basement.
What insurance do new radon mitigators carry?
At minimum, general liability that actually names radon mitigation, plus whatever your state or general contractor clients require. Some programs or GC wrap policies ask for higher limits. Confirm the wording with your agent. A cheap policy that excludes pollution or radon is a paperweight. I would not take a paid job without the certificate in the file.
How soon after installation should you retest?
After the system has run and the house has settled back into closed conditions. EPA's consumer materials treat post-mitigation testing as part of finishing the job, not as an optional extra. Follow the measurement protocol your state or the contract named. Retest again after major renovation, a fan change, or a long outage.
Sources
- U.S. EPA, Health Risk of Radon: EPA attributes about 21,000 U.S. lung cancer deaths each year to radon and treats radon as a leading cause of lung cancer.
- U.S. EPA, A Citizen's Guide to Radon (2016): Defines radon as a radioactive gas from uranium in soils and recommends fixing a home at 4 pCi/L, with consideration of a fix between 2 and 4 pCi/L.
- U.S. EPA, Consumer's Guide to Radon Reduction (2016): A typical residential mitigation system installation costs between $800 and $2,500, and active soil depressurization is the common method.
- U.S. EPA, What is EPA's Action Level for Radon and What Does it Mean?: EPA's action level is 4 pCi/L and EPA recommends considering fixes between 2 and 4 pCi/L.
- National Cancer Institute, Radon and Cancer: Radon exposure is linked to lung cancer risk that increases with higher concentrations and longer time indoors.
- World Health Organization, Radon and Health fact sheet: WHO states radon is the most important cause of lung cancer after smoking and recommends a national reference level of 100 Bq/m3.
- U.S. EPA, Find a Radon Test Kit or Measurement and Mitigation Professional: EPA directs the public to qualified measurement and mitigation professionals and to state radon program contacts because requirements vary by state.
- U.S. EPA, Radon Standards of Practice: EPA points practitioners to current consensus radon standards of practice rather than treating older EPA-only manuals as the living rulebook.
- AARST, ANSI/AARST SGM-SF-2023 Soil Gas Mitigation Standards for Existing Homes: SGM-SF-2023 is the named consensus standard for soil gas mitigation in existing homes, including system design, labeling, and discharge.
- NRPP, Radon Mitigation Specialist Certification: NRPP publishes a Mitigation Specialist certification track with required training and a national exam.
- Iowa Administrative Code 641 Chapter 43, Radon Mitigation: Iowa writes radon mitigation program rules, including who may offer mitigation, in IAC 641 Chapter 43.
- Ohio Administrative Code Chapter 3701-69, Radon Testing and Mitigation: Ohio licenses and regulates radon mitigation specialists under OAC Chapter 3701-69.
- Minnesota Department of Health, Radon Mitigation: State health guidance describes active soil depressurization parts: pipe, fan, rooftop discharge, and a system monitor.