Radon Mitigation in Canada — Systems, Costs & Contractors

When you should mitigate

Health Canada's updated guideline says any home above 200 Bq/m³ should take corrective action to lower radon within one year. The higher the radon concentration, the sooner you should act — readings in the thousands require immediate intervention.

Above 200 Bq/m³ — mitigate within one year; act faster when levels are very high.
100–200 Bq/m³ — below the Canadian action line, but the WHO recommends reducing where practical.

How active sub-slab depressurisation works

The standard Canadian mitigation system is active sub-slab depressurisation (ASD). A contractor cores a hole through your basement slab, inserts a 3- or 4-inch PVC pipe, and routes it up through the house — usually inside a wall or a closet — and out above the roofline. An inline radon fan creates negative pressure beneath the slab, capturing radon gas before it can rise into your living space and venting it safely outside. Well-designed ASD systems reduce indoor radon by 80–99% and run for about the same power cost as a desktop computer.

For homes with crawl spaces, mitigators install a sealed polyethylene membrane and depressurise the space underneath. Homes built on engineered slabs or with multiple foundation sections may need more than one suction point.

What it costs in Canada

A typical single-family Canadian home costs C$2,000–C$4,000 for a complete ASD installation including the fan, manometer, sealing, and post-mitigation test. Complex foundations, finished basements that require careful routing, or homes needing multiple suction points can run C$4,000–C$6,000. Some provinces and municipalities offer rebates — check your provincial environment or health department before you book the install.

How to find a qualified contractor

Hire a mitigator certified by the Canadian National Radon Proficiency Program (C-NRPP). C-NRPP professionals follow Health Canada's mitigation standard, are insured, and warranty their work. You can search the C-NRPP directory online and most certified contractors will quote based on a site visit and your long-term test result.

Verify the system worked

Retest within 30 days of installation to confirm levels are below 200 Bq/m³, then again with a long-term test (or an ongoing real-time monitor) to make sure the system holds up year-round. See our testing guide for the right approach. The system fan should run continuously — switching it off lets radon return within hours.

Can I do it myself?

We do not recommend DIY mitigation. Improper suction-point placement, undersized fans, or unsealed sumps can leave radon levels unchanged or even pull soil gas into living areas. A certified C-NRPP installation includes diagnostic testing, proper venting, and a post-install confirmation test that DIY work rarely matches.

Frequently asked questions

How much does radon mitigation cost in Canada?

A typical single-family Canadian home costs C$2,000–C$4,000 for a complete active sub-slab depressurisation system installed. Complex foundations, crawl spaces, finished basements, or multiple slabs can push the cost to C$4,000–C$6,000 or more.

What is the most effective radon mitigation system?

Active sub-slab depressurisation (ASD) is the standard. A fan pulls radon-laden air from beneath the slab and vents it above the roofline before it can enter the home. Properly designed systems routinely reduce indoor levels by 80–99%.

Will sealing cracks alone reduce radon?

No. Sealing cracks helps a depressurisation system work better, but on its own it rarely brings levels below the Health Canada guideline of 200 Bq/m³.

How do I find a radon mitigation contractor?

Use a contractor certified by the Canadian National Radon Proficiency Program (C-NRPP). Certified mitigators follow Health Canada's installation standard and warranty their work.