What radon mitigation costs
A radon mitigation system costs $800 – $2,500 installed, with the national average near $1,500. That buys sub-slab depressurization: a suction point cut into the slab, a pipe routed up and out above the roofline, an inline fan, and sealing of the cracks and sump lid the system relies on.
Homes over a crawl space cost more, $1,500 – $4,000, because a sealed membrane has to go down before anything can be drawn from beneath it. Houses with additions, split levels or mixed foundation types often need two or more suction points, which puts them at $3,000 – $5,000.
Test before you spend anything
A DIY short-term test kit costs $15 – $35 including the lab fee. A professional measurement with a continuous monitor costs $150 – $300. Either one comes before a single mitigation quote, because the result decides whether there is anything to fix.
The EPA action level is 4.0 pCi/L. At or above that reading, the EPA recommends installing a mitigation system. Below it, the recommendation is to keep the result on file and retest every few years, or after any work that changes how the house handles air — a new HVAC system, a finished basement, foundation repairs, or new windows. A house measuring 1.8 pCi/L today needs a $15 kit in a few years, and nothing else.
Radon levels vary by house rather than by neighborhood, so a high reading next door tells you very little about yours. Test your own house, place the kit in the lowest lived-in level, and follow the closed-house conditions on the instructions. If a contractor offers to test at no charge as part of a quote, that is a fair offer to accept and also a fair one to verify — an independent measurement costs $150 – $300 and answers to nobody selling a system.
Cost by component
| Item | Typical range | Unit | What drives it |
|---|---|---|---|
| DIY short-term test kit | $15 – $35 | per kit | 2–7 days, mailed to a lab |
| Professional radon test | $150 – $300 | per test | Continuous monitor, usually 48 hours |
| Sub-slab depressurization system | $800 – $2,500 | per system | The standard fix; one suction point |
| Crawl space membrane system | $1,500 – $4,000 | per system | Sealed membrane plus suction beneath it |
| Multiple suction points | $3,000 – $5,000 | per system | Additions, mixed foundations, dense fill |
| Sealing floor cracks | $350 – $900 | per crack | Entry paths the system depends on closing |
| Sealed sump cover | $150 – $400 | per sump | An open pit is a direct soil-gas path |
| Post-mitigation retest | $150 – $300 | per test | The proof the system works |
| Inline fan replacement | $200 – $400 | per fan | Fans last roughly 5–10 years |
| Fan electricity | $75 – $200 | per year | Runs continuously, plus a small HVAC penalty |
Source: Compiled from published 2025–2026 contractor cost datasets for residential radon mitigation, EPA consumer guidance on radon reduction, and lab-analyzed test kit retail pricing. Installed costs include labor, materials and electrical work. · Last reviewed July 30, 2026 · Reference data · How we compile these figures
The retest line deserves attention. A system that is running is a system that appears to work; a post-mitigation measurement at $150 – $300 is the only thing that shows the level actually dropped. Ask before signing whether the retest is included, and whether the contractor guarantees a specific post-install reading in writing. Many do.
Cost by system and foundation type
| Home type | Installed cost | System | What drives it |
|---|---|---|---|
| Slab-on-grade home | $800 – $2,000 | Single suction point | Easiest case; pipe routed through the garage or outside |
| Basement, sub-slab depressurization | $1,000 – $2,500 | Single suction point | The most common installation in the US |
| Crawl space, sealed membrane | $1,500 – $4,000 | Membrane plus suction | The membrane is most of the labor |
| Mixed or multi-section foundation | $3,000 – $5,000 | Two or more suction points | Additions and split levels rarely share one slab |
| Activating an existing passive stack | $300 – $800 | Fan and wiring only | Newer homes often have the pipe already run |
| Passive rough-in during construction | $400 – $1,500 | Pipe, membrane, capped stack | By far the cheapest time to do this |
Source: System totals assume a single-family home with accessible foundation walls and an exterior or garage route for the vent stack. Interior stacks routed through finished space, and homes needing more than two suction points, price toward the top of each range. · Last reviewed July 30, 2026 · Reference data · How we compile these figures
Check for a capped pipe stub in the basement or garage before you get quotes. Many homes built in the last two decades already have a passive stack run through the roof, and turning it into an active system means adding a fan and a circuit — $300 – $800 rather than $1,500. Contractors will find it during a site visit, but knowing it in advance changes how you read the bid.
What the system actually does
Radon is a soil gas. It moves upward through the ground and enters a house wherever the foundation is open to the soil — slab cracks, the wall-floor joint, an uncovered sump pit, utility penetrations, or bare dirt in a crawl space. Indoor air pressure that sits slightly below soil pressure pulls it in.
Sub-slab depressurization reverses that pressure difference. A pipe drawing on the gravel layer under the slab creates a low-pressure zone, and the fan carries the soil gas up and out above the roofline before it reaches living space. Sealing cracks and covering the sump is part of the same job, because every open path reduces the suction the fan can hold under the slab.
Three things belong in a bid worth accepting: where the suction point goes and why, where the stack exits and how far it clears windows and the roofline, and what the post-install reading is expected to be. A contractor who walks the house and answers those three specifically is describing your house. On quotes above roughly $3,000, a second opinion from an independent measurement provider is worth the $150 – $300 — particularly for crawl space and multi-suction designs, where the scope genuinely varies between companies.
Running costs, upkeep and DIY
The fan runs continuously and uses $75 – $200 per year in electricity, plus a modest heating and cooling penalty from the air it moves. Fans last roughly 5–10 years and cost $200 – $400 to replace — budget for that rather than meeting it as a surprise.
Maintenance is genuinely light. Check the manometer, the little U-shaped gauge on the pipe: uneven fluid levels mean the fan is pulling. Level fluid means the fan has stopped, and that is your cue to look at it. Retest the house every two years, and after any renovation that changes the foundation or the ventilation.
DIY kits exist for around $300 – $600 in materials, and a capable homeowner with a core drill and electrical skills can install one. The economics are thinner than they look: the labor is one to two days, the electrical work often needs a permit, and an incorrectly sized fan or a poorly placed suction point produces a system that runs without lowering the number. At an average installed price of $1,500 with a guaranteed post-install reading, most homeowners get better value from a certified installer. The part worth doing yourself is the $15 – $35 test that starts the whole conversation.
A few practical notes on quotes. Ask whether the installer is certified through NRPP or NRSB, whether the fan carries its own warranty separate from the workmanship warranty, and what the system is expected to read afterward. Ask where the stack will run — an exterior stack is cheaper, an interior stack through a closet or the garage is quieter and less visible from the street, and the difference is usually a few hundred dollars. If you are buying the house, radon mitigation is a common closing negotiation, and at an average of $1,500 it is one of the more straightforward items to settle with a seller credit.
Related reading: crawl space encapsulation cost, crawl space repair cost, basement repair cost, egress window cost, and sump pump installation cost.