Can you install a radon mitigation system yourself?

Physically, yes. The most common system is a hole cored through the slab, a small pit dug beneath it, sealed PVC pipe and a fan that vents soil gas above the roofline.¹² A handy homeowner can build that. Whether you're allowed to is a state and local question, so check before you drill. And the job isn't done until a retest shows the level fell.³

TL;DR

• Test before you build anything. EPA says to fix a home at 4 pCi/L or higher and to consider fixing between 2 and 4 pCi/L.⁴
• The DIY version is active soil depressurization, the same system pros install most often.¹ The hard parts are picking a suction point, sealing every opening and venting the gas safely.
• Rules on who may install a system vary by state, and a permit may apply. Ask your state radon program and your building department before you core the slab.
• Retest within 30 days of turning the fan on, then every two years.³ If the number is still 4 pCi/L or higher, bring in a certified mitigator.
• Finishing the basement? Settle radon first, while the slab and sump are still exposed.

Can I install my own radon mitigation system?

Yes, many handy homeowners can. Active soil depressurization is the most common home system. An exhaust fan pulls radon from the soil under the foundation, draws it up a pipe and vents it outdoors above the roofline.¹ The work is concrete coring, PVC plumbing and a fan circuit. The legal side depends on your state and town.

The skills are ordinary. The hard part is reading the house before you choose where suction goes, and some houses make that tricky.

One radon contractor lists conditions that complicate a retrofit. A high water table may need more suction points. Ductwork or utilities in the slab should be removed or sealed. Radiant heat tubing below the slab often takes a thermal imaging camera to find.⁵ Coring into a heat loop is a costly mistake. If your slab has radiant heat, hand this job to a pro.

Warranty is another quiet cost. HomeGuide notes that most manufacturers offer a 5-year warranty on radon fans for professionally installed systems.¹ Ask the fan maker what applies to a self-install before you buy.

Who is allowed to do the work

Radon rules are set state by state. New York, for example, sends homeowners to its list of certified radon mitigators. It also requires mitigators to report their number of mitigations to the state health department.³ A radon contractor in Connecticut says EPA recommends at least state-level certification for the contractor.⁵ Nationally, installers can hold NRPP or NRSB certification.¹

None of that answers whether you may install a system in your own home. Ask two offices before you buy parts:

• Your state radon program. Ask whether a homeowner may install a system in their own house, and which standard it must meet.
• Your local building department. Ask whether you need a permit and an inspection. HomeGuide puts radon permit fees at $25 to $150, depending on location.¹

The standard behind the answer matters too. New York's health department says the AARST/ANSI national radon standards are the currently accepted standards for mitigation and supersede previous EPA standards.³ Build to whatever your state names.

Selling later is another reason to keep records. HomeGuide advises checking your state laws on whether radon testing is required before a sale.¹ Keep your permit, your test results and photos of the install.

Can radon go through a concrete slab?

Yes, mostly through its cracks, joints and openings. The New York State Department of Health lists cracks in the slab, slab-footing joints, pores in concrete block, exposed soil in a sump, gaps between slab and block walls and loose-fitting pipes as radon entry points.³ A mitigation system pulls soil gas away before it reaches those gaps.

Sealing sits at the center of a DIY install. The fan works by holding the soil under the slab at lower pressure than the room above. Every open crack lets house air leak down into the system instead.

Forum installers make the same point. One says to fill all test holes, cracks and joints so the pull of air comes from under the slab, because too many holes defeat the fan.² Another warns that an unsealed sump pit lets the fan suck air from inside the house.⁶ That poster sealed the pits with vapor barrier plastic and tape, and cuts the tape when he needs to check the pump.⁶

A tighter basement can also raise radon. One forum homeowner said his level sat well below 4.0 pCi/L until the rim joists were sealed and insulated.² After that, he wrote, radon "started to pool up."² That's one person's report. New York's health department separately advises testing after major renovations.³

How can I mitigate radon myself?

A DIY sub-slab system takes seven steps: test, choose a suction point, core the slab, dig a pit, set and seal the pipe, run the pipe to a fan and vent, then retest. The main parts are a core drill, PVC pipe and fittings, sealant, a radon fan, a manometer and a power supply for the fan.

The steps below draw on a detailed DIY forum walkthrough plus state and EPA guidance. Treat the forum figures as one experienced homeowner's method. Your state's standard wins where they differ.

1. Confirm the level with a test

A home radon test kit costs $10 to $30, and some states give free short-term kits.¹ New York sells state homeowners a kit for $12.25.³ Keep windows and doors closed for 24 hours before and during the test.³ EPA's line is simple: fix at 4 pCi/L or higher, and consider fixing between 2 and 4.⁴

2. Pick the suction point

The forum method puts the hole at least 12 inches from the foundation wall to miss the footing.² Under a gravel base, the poster says it can go almost anywhere because gravel has lots of air space.² Pros also use sump-hole suction or drain tile suction when a house has them.⁵ If you'd rather keep the sump out of the system, pick a separate spot. Still seal the sump, but in a way you can open to check the pump.⁶

3. Core the slab and dig a pit

The same walkthrough marks a 4.5 inch hole even for 3 inch pipe, so you can reach in and dig.² Posters in two forums put the pit at roughly a 5-gallon bucket of fill.²⁶ The void gives the fan room to pull soil gas from around the pit.

4. Set and seal the pipe

The forum poster prefers 4 inch pipe, accepts 3 inch, and says to use 4 inch if your level is above 10 pCi/L.² He wraps backer rod around the pipe to seal the hole, hold the pipe and damp vibration.² Another reply adds silicone or polyurethane sealant and rubber straps so fan hum doesn't carry into the floor.²

5. Run the pipe, fan and vent

Slope any horizontal run back toward the slab hole so condensation drains into the ground.² A British Columbia owner-builder used a quarter inch of fall per foot.⁷ The fan goes in the attic or outside the house.¹ The forum method adds a condensate bypass at the fan.²

Where the pipe ends is a code question, and the two DIY sources disagree. The DIY Chatroom poster says at least 1 foot above the roof line.² The British Columbia builder cites that province's building code: 6 inches above the roof and 10 feet from any window, or 2 feet above it.⁷ Neither is your rule. Get the termination height and window distance from your state's standard or your inspector.

6. Power the fan and fit the manometer

A radon fan runs all the time. HomeGuide says it uses about as much power as a 60-watt bulb, around $70 to $80 a year.¹ If you need a new outlet or circuit, hire a licensed electrician. A U-tube manometer on the pipe shows suction in inches of water column. It should read near your fan's rated suction when running and zero when off.² Label the pipe as a radon system so nobody cuts into it later.

7. Retest

The forum poster checks levels after the fan has run a few days to a week.² New York says to test within 30 days of installing a system, then every two years to confirm it still works.³ Most homes can be brought to 2 pCi/L or below.³ If you're still at 4 or higher, bring in a certified mitigator.

DIY parts and what each one does

What hiring it out costs

Price the pro option before you commit a weekend. The two reference figures differ in scope. HomeGuide's range is a national average for installed systems. New York's figure is that state's average. Budget from the national range, then check local quotes. For the full breakdown, see what radon mitigation costs.

What are the odds of a house having radon?

About 1 in 15 US homes has high radon, based on the EPA figure HomeGuide reports.¹ Where you live doesn't rule it out. EPA says its radon zone map should not be used to decide whether a single home needs testing.⁴ Homes with high levels turn up in all three zones.¹ A test is the only way to know.

Geography still shifts the odds. HomeGuide says high radon is more common in cold climates with rocky or dry soil.¹ The EPA zone map dates from 1993 and was built to help governments target their work.⁴ It can't tell you what's under your slab.

For scale, EPA puts the average indoor level at 1.3 pCi/L and the average outdoor level at 0.4 pCi/L.⁸ A reading of 4 works out to about three times that indoor average.

Can you live in a home with high radon?

EPA's advice is to fix it. It recommends fixing any home that tests at 4 pCi/L or higher.⁴ At that level over a lifetime, EPA estimates about 7 in 1,000 people who never smoked could get lung cancer, and about 62 in 1,000 who smoked.⁸ The risk rises with the level and with time.

EPA calls radon the leading cause of lung cancer among non-smokers and the second leading cause overall.⁸ It estimates about 21,000 radon-related lung cancer deaths a year, about 2,900 of them among people who never smoked.⁸ In 2005 the US Surgeon General urged Americans to fix homes at 4 pCi/L or more as soon as possible.⁸

The practical answer is to plan the fix now and not wait a season. If a DIY build would take you months to start, a pro install may be the lower-risk choice.

Does opening windows reduce radon?

A little, for as long as they're open. HomeGuide says opening windows and doors adds natural ventilation that lowers radon slightly, but it isn't an effective long-term fix.¹ Open windows also skew tests. New York's health department says to keep windows and doors closed for 24 hours before and during a radon test.³

Mechanical ventilation also helps, within limits. HomeGuide says ventilation systems such as energy recovery or heat recovery ventilators also reduce radon, though they aren't as effective as other systems.¹ Contractors typically use them only when a home lacks room for a sub-slab system.¹

The forum homeowner whose radon rose after sealing his rim joists described the old leaks as "almost like having the window open 24hrs a day."² Air leaks were diluting his radon. Closing them without a suction system let it build.

Settle radon before you finish the basement

Basement Remodeling Co. treats radon as a before-framing job. Test and fix the level while the slab, sump and walls are still bare. Finished walls and ceilings hide the cracks you need to seal and the route the pipe needs to run. Then retest after the renovation, as New York's health department advises.³

New York notes that building a system in during construction is easier and cheaper than adding one to a finished house.³ The same logic applies to a basement build-out. A pipe run planned before framing can go in a closet or a corner chase. A pipe added after drywall means cutting finished walls.

Radon and water often use the same openings. New York lists exposed soil in a sump and water among radon entry points.³ A sump pit or perimeter drain can also serve as a suction point.⁵ If you're also dealing with water, read how basement waterproofing works before you finish. For how the system types compare side by side, see our guide to radon mitigation system types and costs.

When you're ready to get a written quote for finishing your basement, mention your radon result and any system you've installed at the free on-site estimate. Your contractor can plan the layout around the pipe, fan access and manometer. You can also find the basement contractor who covers your ZIP code. If your basement is already finished, start with what remodeling an existing basement involves. Local pages cover finishing a basement in metro Denver and finishing a basement in metro Atlanta.

What to ask a radon mitigator before you hire

If you decide to hire the work out, these questions sort a good quote from a vague one. Most come from HomeGuide's hiring checklist.¹

• Are you NRPP or NRSB certified, and do you hold any certification my state requires?
• What system do you recommend for this house, and why there?
• Does the price include the permit and a follow-up test?¹
• How much do you expect the level to drop?
• What does the fan warranty cover, and for how long?
• Which standard will you install to?

Pay a partial deposit and get a receipt. HomeGuide advises never paying in full before installation.¹