How to Choose a Radon Mitigation Contractor in South Carolina

Updated October 2026 · 5 min read

Once you have a high radon test, the next step is finding someone to fix it. In the Upstate, a search turns up a mix of local companies, national franchises and directory listings, and it can be hard to tell them apart. This guide gives you a simple way to compare them.

South Carolina has no state radon license

Start with the fact that surprises most people: South Carolina does not have a state license for radon testers or mitigators. There is no state board checking qualifications before someone installs a radon system in your house.

That does not mean anything goes. It means the homeowner has to do a bit more checking. The main tool you have is national certification.

Look for NRPP or AARST certification

In the absence of a state license, the credentials to look for come from national programs: the National Radon Proficiency Program (NRPP) and the American Association of Radon Scientists and Technologists (AARST). These programs certify individual radon professionals for testing and for mitigation.

A few practical tips:

• Ask which person holds the credential. Certification belongs to an individual. Ask whether the person designing or installing your system holds it.
• Ask for the credential number and check that it is current.
• Make sure it covers mitigation, not only testing, if they are installing a system.

Speaking for ourselves: we are happy to share the credentials of the technician assigned to your job. Just ask when you request a quote.

What a good contractor does before quoting

Looks at your test result

A good contractor starts with your number. Was it a short-term or long-term test? Was it on the lowest lived-in level? Was the house closed for 12 hours before and during a short-term test? If the test is questionable, they should say so.

Looks at the house

Many Upstate homes sit on crawl spaces or slabs, and older homes may have basements. Some have a mix. The right system depends on the foundation, the soil and how the pipe can be routed. A contractor who quotes a firm price without seeing the house, or at least detailed photos, is guessing.

Does diagnostics when it makes sense

On many homes, contractors check how air moves under the slab or membrane before settling on where to put suction points and which fan to use. Ask how they decide on the design.

What a good written quote includes

Get the quote in writing, and make sure it covers:

• The type of system: sub-slab depressurization, crawl space sub-membrane or a combination
• Number and location of suction points
• Pipe routing: exterior, interior and attic, or through a garage
• Fan location and model
• Sealing work, such as cracks, sump pits or the crawl space membrane
• Electrical work needed for the fan
• A post-mitigation radon test and who does it
• Permits where your city or county requires them
• Total price and what could change it

For reference, typical ranges in the Upstate are $900–$2,500 for sub-slab depressurization, $1,500–$3,500 for a crawl space sub-membrane system and $2,200–$3,800 for combination foundations. These are estimates; final prices come after an on-site look. See our radon mitigation cost guide for what moves the number.

What a good install looks like

• The fan is outside the living space, outdoors or in the attic, never in a basement or living area.
• The vent discharges above the roofline, away from windows and openings.
• A manometer is installed so you can see the system is pulling suction.
• The system is labeled so future owners, inspectors and contractors know what it is.
• The work area is left clean, with penetrations sealed and pipe neatly supported.
• A post-install radon test confirms the level dropped. The EPA recommends retesting after mitigation, and you should see the result in writing.

Our process page shows how we handle each of those steps.

Red flags

Be cautious if a contractor:

• Quotes a firm price sight unseen for a home with an unusual or mixed foundation.
• Will not tell you who holds the credentials or will not share a credential number.
• Does not include a post-mitigation test, or discourages you from testing yourself.
• Promises a specific radon number before anyone has looked at the house.
• Uses scare tactics or pressure, like "the price is only good today."
• Wants to put the fan inside the living space or vent the pipe at ground level near windows.
• Is vague about permits in a place that requires them.
• Pushes extras you did not ask about without explaining why your house needs them. Crawl space encapsulation, for example, can be worth doing, but it is a separate project with a typical range of $1,500–$15,000 depending on size and condition, and it is not required for a radon system to work.

Questions to ask on the phone

1. Who will design and install my system, and what credentials do they hold?
2. Will you look at the house before giving a final price?
3. What type of system do you expect, and where would the pipe and fan go?
4. Is a post-mitigation test included?
5. Are permits needed where I live, and who pulls them?
6. How long will the install take? (A typical install takes a few hours; complex homes can take up to a day.)
7. What happens if my follow-up test is still high?

Bottom line

With no state license in South Carolina, the best protection is a contractor who is open about credentials, looks at your house before committing to a price, puts the details in writing and proves the result with a post-install test. If you are on a home-sale deadline, our guide to radon when buying or selling in SC covers timing, and we serve homes across the Upstate, from Greenville to Spartanburg and Anderson.

Frequently asked questions