Radon mitigation cost: every published figure, compared

Radon mitigation means installing a system that keeps radon out of a home's air. Almost always that is a vent pipe and a fan that draw soil gas from under the foundation and release it above the roof. This soil suction system is the main method in use, and it does not require major changes to a home. What it costs depends on the house more than on anything else, so this page lays out every figure a public agency has published, side by side, and then explains what moves your own quote up or down.

Each bar is one publisher's figure for installing a system in an existing home, in the dollars of the year it was published. A dot is a single figure (an average or an approximate cost), and a fading bar marks a figure stated as a ceiling ("less than") or a floor ("or more"). None of these is our estimate, and none is adjusted for inflation. To use the chart with a quote in hand, find your own state's bars first, then EPA's: a quote far below every published range may leave out part of the job, and one far above deserves a line-by-line explanation from the contractor. To see only the figures that apply to your state and foundation, use the mitigation cost estimator.

The cost of a system varies with the size and design of the home, which reduction methods it needs, the materials, and how big the radon problem is. In practice that comes down to the parts of the job below.

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1. 1Soil gas drawn from beneath the slab
2. 2Suction point through the slab
3. 3Vent pipe
4. 4Fan, outside the living space
5. 5Discharge above the roofline

Foundation type

Homes are grouped by foundation: a basement, a slab-on-grade (concrete poured at ground level), or a crawlspace (a shallow unfinished space under the first floor). Each takes a different method, and a home with more than one foundation feature may need a combination of techniques. Utah's environment department says its $1,800 average depends primarily on the type of foundation and the size of the home. The cost by foundation type section has the figures.

Number of suction points

How many suction pipes a slab needs, and where, depends on how easily air moves through the crushed rock or soil under it and on how strong the radon source is. Often a single suction point is enough. Each one is a pipe set through the floor slab into the material underneath, so every added point is more of the job.

Sump pits and drain tile

A home with a sump can sometimes use it: the sump can be capped so that it still drains water and also serves as the place for a suction pipe. Utah's environment department says homes with sump pumps, French drains or a buried water-collection loop can be mitigated by connecting the system to that water control system. Illinois, by contrast, requires a primary suction point separate from the sump pit. Where your state draws that line changes what a contractor has to build.

Inside or outside pipe routing

The pipe can run inside or outside the home. Fans usually go in unconditioned spaces such as an attic or garage, or on the outside of the house, and a fan mounted outdoors must meet local building codes for exterior use. A contractor will usually recommend one route or the other, and routing is one of the choices that differ between quotes for the same house. A cheaper route may look less tidy.

Finishing, sealing and electrical work

Sealing cracks and openings is part of the job, because it limits how much radon gets in and makes the other techniques more effective and cost-efficient. Most installations also need electrical work to power the fan, done to local electrical codes and, in Minnesota, under an electrical permit. Openings a mitigator cannot reach, such as cracks under covered floors, can make a system less effective or more costly to run.

Diagnostics and testing

Many contractors give free estimates but may charge for diagnostic tests, which use a vacuum cleaner and chemical smoke to see how easily air moves under the foundation. Whether these are needed depends on the foundation design, the material under the home and the contractor's experience with similar homes. A test after installation is part of the job too; the testing cost page has what tests cost.

These are the states whose health or environment departments publish a cost figure for mitigation, with the year of each. A state that is not here has not published a figure on its radon pages. Its radon program can still tell you what local contractors charge, and many keep a list of licensed or certified mitigators. Find yours on the state radon programs page.

The fan is the one part that wears out. Fans may last five years or more, and manufacturer warranties tend not to run past five years. South Dakota gives an expected fan life of 11 years, and Utah says to plan on replacing the fan after about 15 years.

Beyond the fan, upkeep is small. A system takes little effort to maintain: look at its warning device, usually a manometer, on a regular basis. Minnesota's health department says to check the fan monitors monthly and to retest the building for radon at least every two years. When the system goes in, ask the contractor to explain it, show how it works and how to maintain it, and to give you written operating and maintenance instructions and copies of any warranties. Read the conditions of any guarantee carefully: many contractors guarantee to adjust or modify the system to reach an agreed radon level, often 2 pCi/L or less. The radon fan guide covers how to tell a fan has stopped and what replacement involves.

Get more than one estimate, ask each contractor for references, and call some of them. Wisconsin's health department recommends contacting at least three companies, Illinois's radon program says to request two or three price estimates from licensed professionals, and the University of Georgia's program says to get more than one estimate in writing.

1. 1

   Confirm the result first

   EPA recommends fixing a home if one long-term test, or the average of two short-term tests, shows 4 pCi/L or more. A single short-term result is a reason to follow up, not yet to buy a system.

2. 2

   Find qualified contractors

   Many states require radon professionals to be licensed, certified or registered. Where a state does not (Georgia, for one, has no requirement that mitigators be certified), ask whether the contractor holds a credential from the National Radon Proficiency Program (NRPP) or the National Radon Safety Board (NRSB).

3. 3

   Have each one inspect the house

   A good estimate comes after the contractor has looked at the home's structure and reviewed the quality of your radon test results.

4. 4

   Compare the same scope

   Line up suction points, fan, pipe route, sealing, electrical work and permits, the warning device and the follow-up test across every quote, so the totals compare like with like.

5. 5

   Get a written contract

   It should state the total cost of the job, including all taxes and permit fees; any deposit; when payment is due in full; how long the work will take; and the details of any guarantee to bring radon below an agreed level.

6. 6

   Test after installation

   Test within 30 days of installation, but no sooner than 24 hours after the system starts running. An independent follow-up measurement is recommended.

On price alone, keep in mind that a cheaper system may cost more to run and maintain, that a more expensive system may be the right one for your home, and that the quality of the materials affects how long the system lasts. We do not sell leads: the mitigation professionals directory takes you to each business directly.

Some states allow it, and the parts cost a fraction of an installed system, but every agency is cautious. EPA recommends a qualified radon mitigation contractor, because lowering high radon levels takes specific technical knowledge and skills, and without the right equipment or knowledge you could raise your radon level or create other hazards and costs. Illinois lets residents install a system in their own home, with the same warning, and Wisconsin's health department says sub-slab depressurization is not a do-it-yourself project unless you have considerable contractor skills.

Radon in a private well is treated where the water enters the house, with an aeration system or a granular activated carbon (GAC) filter. GAC filters usually cost less than aeration, but they can collect radioactivity and may need a special method of disposal. Radon from the soil is usually a much larger risk than radon from water, so test the air first. When a quote names one treatment, compare it with that treatment's figure below; Massachusetts' range covers either kind. The radon in water treatment cost page has the detail.