Radon and Real Estate in BC: What Buyers and Sellers Need to Know

Radon has become one of the most common environmental concerns in BC real estate transactions. Buyers are requesting tests as conditions of purchase. Sellers are being asked to disclose. And realtors are navigating what the results actually mean for a deal.

This guide explains what buyers, sellers, and their agents need to know — from disclosure obligations to which test counts, and what elevated results mean for negotiations. BC Radon Control is C-NRPP certified for both testing and mitigation throughout the Fraser Valley.

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Radon as a Material Latent Defect in BC

In BC, sellers are legally obligated to disclose material latent defects — defects that are not visible on inspection and that could render the property dangerous or unfit for habitation. The BC Financial Services Authority (BCFSA) has specifically identified elevated radon levels as a material latent defect that sellers are required to disclose if they are aware of it.

What this means in practice:

• If a seller has had a radon test showing levels above Health Canada’s guideline of 200 Bq/m³ and has not mitigated, that result must be disclosed.
• If a seller has never tested, there is no obligation to disclose what they don’t know — but buyers should insist on testing as a condition of purchase.
• A mitigated home is not necessarily a defect — if a mitigation system is in place and the home tests below 200 Bq/m³, the seller’s disclosure typically notes the system, not a defect.

The practical implication for sellers: If you know you have elevated radon and haven’t fixed it, you must disclose. If you’re planning to sell, testing and mitigating before listing puts you in a stronger position — a mitigated home at 25 Bq/m³ is a feature, not a liability.

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What Test Is Required for a Real Estate Transaction?

Not all radon tests are created equal, and for real estate purposes, the type of test and who conducts it matters.

The accepted standard: 96-hour C-NRPP short-term test

For real estate transactions, the accepted test is a short-term test of at least 96 hours conducted by a C-NRPP certified measurement technologist using commercial-grade continuous monitoring equipment. This is what BC Radon Control provides.

DIY test kits are not appropriate for real estate. A mail-in alpha track test placed in a bedroom and returned after 90 days will not satisfy a buyer’s realtor, their lender, or the conditions on the contract.

What a C-NRPP short-term real estate test provides:

• A tamper-evident electronic record of continuous hourly readings over the test period
• Closed-home conditions verified and documented
• A signed report from a certified technologist that satisfies purchase condition requirements
• Results typically available within 2–5 days of test pickup

Timing and conditions

For a radon test to be valid under C-NRPP protocols:

• Closed-home conditions must be maintained during the test — windows and exterior doors kept closed except for brief entries and exits
• The test device is placed in the lowest livable level of the home
• The device runs for a minimum of 96 hours (4 days)

Buyers writing a subject-to-radon-test condition should allow at least 5–7 days for test placement, closed-home period, and report turnaround.

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How to Interpret Results During a Transaction

After the test, the certified report shows an average radon concentration in Bq/m³. Here’s what the levels mean in the context of a real estate deal:

Result	What it means	Typical negotiating position
Under 100 Bq/m³	Well below Health Canada guideline	Condition typically removed without issue
100–200 Bq/m³	Below the action level but above WHO guidelines	Buyer may accept or request a credit toward future mitigation
200–600 Bq/m³	Above Health Canada’s action level	Buyer typically requests mitigation before closing, a price reduction, or a holdback
Over 600 Bq/m³	Significantly elevated	Immediate mitigation required; deals frequently renegotiate on price or close conditional on completed work

A note on short-term vs. long-term accuracy

Short-term tests are less precise than 91-day alpha track tests — they’re a snapshot, not an annual average. A reading of 215 Bq/m³ on a short-term test does not mean the home is definitively at 215 Bq/m³ year-round. Seasonal variation, weather, and home conditions can affect short-term readings in either direction.

This matters because minor elevations above 200 Bq/m³ on a short-term test warrant further investigation, not panic. A follow-up long-term test after possession is often a reasonable compromise when short-term results are borderline.

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Budgeting for Mitigation as a Buyer

If you’re purchasing a home and radon testing reveals elevated levels, knowing what mitigation actually costs helps you negotiate clearly.

In the Fraser Valley, professional radon mitigation by a C-NRPP certified contractor typically ranges from $2,500 to $3,800 for a standard residential installation. This includes:

• Site diagnostic (sub-slab pressure field testing)
• Drilling, pipe routing, and fan installation (typically one day)
• Sealing visible cracks and penetrations
• Post-installation verification test
• Warranty documentation

Systems last 20+ years and reduce radon levels by 80–95%. A home with a properly installed mitigation system and a verified post-mitigation result under 100 Bq/m³ is not a liability — it’s a home where the radon issue has been professionally resolved.

When requesting a price adjustment or holdback for radon, a quote from a C-NRPP certified contractor gives both parties a factual number to work from.

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What Sellers Should Do Before Listing

If you’re preparing to sell and haven’t tested your home, the smartest move is to test now — before listing — so you know what you’re dealing with.

If results are below 200 Bq/m³: You can disclose that you’ve tested and the home is within Health Canada’s guideline. This is a positive data point, not a problem.

If results are above 200 Bq/m³: You have two choices:

1. Mitigate before listing. A mitigation system typically pays for itself in a smoother transaction and stronger negotiating position. Fraser Valley mitigation costs $2,500–$3,800. Buyers are less likely to request large price reductions on a home where the issue is already resolved and verified.
2. Disclose and price accordingly. Some sellers choose to disclose elevated radon and factor the expected mitigation cost into the listing price. This works, but it hands the buyer negotiating leverage.

In either case, working with a C-NRPP certified contractor — one whose report will be accepted by the buyer’s realtor and lender — is essential.

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Radon and Strata Units

For buyers and sellers in strata buildings, radon is more complicated. Ground-floor and below-grade units carry the most risk. Strata corporations are increasingly being asked to test common areas and underground parking, but individual unit owners typically bear responsibility for testing and mitigating their own suites.

If you’re buying a below-grade strata unit, a short-term radon test as part of your subject conditions is strongly recommended — regardless of whether the strata has tested common areas.

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Getting a Radon Test for Your BC Real Estate Transaction

BC Radon Control is C-NRPP certified for both radon measurement and mitigation, serving the Fraser Valley including Abbotsford, Chilliwack, Langley, Mission, Maple Ridge, Hope, and White Rock.

For real estate transactions, we provide 96-hour short-term tests with certified reports accepted for purchase conditions. We also provide free mitigation quotes for buyers and sellers evaluating remediation options.

If you’re in the Fraser Valley and need a certified radon test for a real estate transaction, contact BC Radon Control for a free quote. For more on the testing process, see our radon testing services page. For mitigation costs and what the installation involves, see how much radon mitigation costs in BC.