Introduction: The Silent Gas You Can’t Afford to Ignore

You can’t see it. You can’t smell it. You can’t taste it.

Yet, radon gas could be quietly accumulating beneath your home right now — and you’d never know until it’s tested.

Radon is an odorless, radioactive gas that naturally forms when uranium breaks down in soil and rock. It seeps into homes through foundation cracks, drains, sump pumps, or gaps in floors and walls.

Over time, radon exposure can be deadly. According to Health Canada, it’s the second leading cause of lung cancer, responsible for more than 3,000 deaths annually. The U.S. EPA estimates it kills around 21,000 Americans every year.

The good news?

Radon problems can be fixed — permanently.

But homeowners often wonder:

“Once I find high radon levels, how long does radon removal actually take — from start to finish?”

This comprehensive guide walks you through every stage of the radon removal process — from the first test to post-mitigation verification — and explains exactly how long each step takes.

1. The Radon Removal Timeline at a Glance

Radon mitigation (or removal) doesn’t happen overnight, but it’s faster than most homeowners expect.

Here’s a breakdown of the typical timeline from discovery to safe air:

StageTaskAverage Time

Step 1 Initial Radon Testing 2–7 days

Step 2 Analyzing Results 1–2 days

Step 3 Hiring a Certified Radon Specialist 1–5 days

Step 4 Radon System Design Site Assessment 1 day

Step 5 Installation of Mitigation System 4–8 hours

Step 6 Post-Mitigation Testing 2–7 days

Step 7 Follow-up Certification 1–3 days

✅ Total Duration: About 1–2 weeks for complete removal from start to finish.

If you include long-term verification (90-day retesting), the process can extend to 3–4 months, but the home is safe to occupy much sooner.

Let’s go step-by-step through the full process.

2. Step 1 – Radon Testing: Detecting the Problem (2–7 Days)

Before you can fix radon, you must confirm that it’s present — and at what level.

Radon testing is the first stage of the removal process.

There are two types of radon tests:

Short-Term Test (2–7 Days)

Short-term tests give a quick snapshot of radon levels.

They use charcoal canisters, electret ion chambers, or continuous radon monitors to measure air concentration.

• Duration: Minimum 48 hours, ideally 4–7 days
• Accuracy: Good for initial screening
• When to Use: During home inspections, or when you suspect high radon

Pro Tip: Keep all windows and exterior doors closed during testing to maintain stable indoor air pressure.

Long-Term Test (90+ Days)

Long-term tests give a more accurate annual average of radon exposure.

These use alpha track detectors that record radiation over time.

• Duration: 90–365 days
• Accuracy: Excellent for long-term exposure evaluation
• When to Use: After short-term test results are borderline (near 200 Bq/m³ or 4.0 pCi/L)

For radon removal, most specialists rely on a short-term test to detect high levels quickly. Once results show dangerous levels, mitigation planning begins immediately https://ottawaradon.pro/.

3. Step 2 – Analyzing Results and Deciding to Mitigate (1–2 Days)

Once your test results arrive, you’ll see your home’s average radon concentration in either:

• Becquerels per cubic meter (Bq/m³) – Canada
• Picocuries per liter (pCi/L) – U.S.

Here’s how to interpret them:

Radon LevelHealth Canada RecommendationAction Needed

Below 200 Bq/m³ (4.0 pCi/L) Safe Retest every 2–3 years

200–600 Bq/m³ Moderate Fix within 2 years

Above 600 Bq/m³ High Fix within 1 year (or immediately)

If your test shows above 200 Bq/m³, mitigation is strongly advised.

Homeowners usually schedule an appointment with a certified radon mitigation professional right after receiving results.

4. Step 3 – Hiring a Certified Radon Specialist (1–5 Days)

The next step is finding a qualified expert.

In Canada, radon mitigation professionals are certified through the Canadian National Radon Proficiency Program (C-NRPP).

In the U.S., the equivalent certification is the National Radon Proficiency Program (NRPP).

How Long It Takes:

• Research and contact local specialists: 1–2 days
• Receive quotes and inspection dates: 1–3 days

Tip: Choose a certified radon contractor who offers both testing and mitigation — this ensures seamless service and accountability.

When booking, ask these questions:

• How long will installation take?
• What system type do you recommend for my home?
• Is post-mitigation testing included?
• Do you provide a warranty?

5. Step 4 – Home Inspection and System Design (1 Day)

Once you’ve hired a professional, they’ll perform a site assessment to design the most effective mitigation system.

This process usually takes a few hours to one full day.

During the Inspection:

• The specialist identifies entry points (cracks, sump pits, wall joints)
• Checks the foundation type (slab-on-grade, basement, crawl space)
• Evaluates airflow and mechanical ventilation
• Determines the best location for the vent pipe and fan

They may use diagnostic tools like:

• Smoke tests to trace air flow
• Pressure field extension measurements to find radon pressure zones

Based on this, the expert recommends a sub-slab depressurization system — the gold standard for radon removal.

6. Step 5 – Installing the Radon Mitigation System (4–8 Hours)

Here’s the good news: actual installation is fast — most systems are installed in a single day.

Average Installation Duration:

4–8 hours for standard homes

8–12 hours for larger or complex layouts

Let’s break down what happens during installation.

Step 5.1 – Drilling the Extraction Hole

A small hole (4–6 inches wide) is drilled through your basement slab or foundation to access the soil beneath.

This creates a suction point where radon gas can be extracted.

Time: 1–2 hours

Step 5.2 – Installing the Vent Pipe

PVC piping is fitted from the extraction point up through the home — usually through the garage or exterior wall — and extends above the roofline.

This pipe safely vents radon gas outside.

Time: 1–2 hours

Step 5.3 – Adding the Radon Fan

A specialized radon fan is installed in the attic, garage, or outside the house. It continuously pulls radon gas from below the foundation and vents it outdoors.

The fan runs 24/7 and is nearly silent.

Time: 1–2 hours

Step 5.4 – Sealing Entry Points

To improve efficiency, technicians seal cracks, joints, and sump lids with airtight caulk or polyurethane sealant.

This prevents radon from re-entering.

Time: 1 hour

Step 5.5 – System Testing and Power Connection

The system is connected to power, and airflow is tested to ensure proper suction.

A manometer (pressure gauge) is attached to the pipe to show whether the fan is running correctly.

Time: 30–45 minutes

✅ Total Installation Time:

4–8 hours (same day completion)

Your home is now equipped with a working radon removal system — but the process isn’t complete until results are verified.

7. Step 6 – Post-Mitigation Testing (2–7 Days)

After installation, the radon specialist conducts a post-mitigation test to verify that radon levels have dropped to a safe range.

This test usually begins 24 hours after installation to allow air circulation to stabilize.

Post-Test Duration Options:

• Short-Term Test: 48–96 hours (most common)
• Continuous Radon Monitor (CRM): 2–7 days (used by professionals)

During this time, the technician may leave a digital monitor or sealed canister in the basement or lowest livable area.

After the test, results are analyzed — either immediately (CRM) or within 1–2 days (lab kit).

✅ Goal:

Radon levels should be below 200 Bq/m³ (4.0 pCi/L) after mitigation.

If levels remain high, the contractor may adjust fan speed, add suction points, or re-seal areas.

8. Step 7 – Certification, Documentation, and Warranty (1–3 Days)

Once successful test results are confirmed, you’ll receive a mitigation completion report and, in most cases, a system performance warranty.

This includes:

• Before-and-after radon level comparison
• System diagram and installation details
• Maintenance instructions
• Warranty information (usually 5–10 years for fans)

The contractor may also file documentation with your local environmental authority or provide proof of compliance for real estate transactions.

9. Optional Step – Long-Term Follow-Up Testing (90+ Days)

For maximum peace of mind, most experts recommend a long-term test (90+ days) a few months after installation.

This confirms that radon levels remain low across different seasons.

• Duration: 3–12 months
• Device: Alpha track detector
• Goal: Verify consistent mitigation performance year-round

Many radon specialists include a discounted or complimentary long-term follow-up test as part of their service.

10. Factors That Can Affect Radon Removal Time

While most installations take less than a day, certain variables can extend the timeline.

1. Home Size and Design

Larger homes or multi-foundation layouts may require multiple suction points or fans, increasing installation time by several hours.

2. Foundation Type

Foundation TypeAverage Installation Time

Basement 4–6 hours

Slab-on-grade 4–8 hours

Crawl space 6–10 hours (requires sealing or liner installation)

3. Accessibility

If the home’s layout makes it difficult to run vent pipes (e.g., finished basements, complex framing), extra drilling or rerouting may add 1–2 hours.

4. Weather Conditions

Rain or freezing conditions can slow drilling or external venting work. Some technicians may delay exterior pipe sealing until dry weather returns.

5. Permits and Scheduling

In some municipalities, a simple permit or inspection may be required for electrical hookup or exterior venting — adding 1–3 days depending on availability.

6. Homeowner Decisions

The overall timeline also depends on how quickly homeowners:

• Approve the quote
• Schedule installation
• Complete pre-install prep (like clearing basement access)

Prompt communication helps speed everything up.

11. What Happens After Radon Removal Is Complete

After installation and verification, the radon fan runs continuously 24/7 to keep radon levels suppressed.

You’ll barely notice it — the fan is quiet and energy-efficient, costing only about $75–$100 per year to operate.

Maintenance Tips:

• Check the system’s manometer monthly (the liquid level should stay uneven — that means it’s working).
• Replace or service the fan every 5–10 years.
• Retest every 2–3 years to confirm continued performance.

If levels ever rise again, a certified technician can recalibrate or expand the system.

12. How Long Until Your Home Is Safe to Occupy Again?

One of the most reassuring facts about radon removal is that your home is safe almost immediately after installation.

Here’s how it works:

• The mitigation system starts venting radon gas as soon as it’s turned on.
• Radon levels typically drop by 80–99% within 24–48 hours.
• You can safely use your basement or lower level again within 1–2 days.

Still, professional post-testing ensures peace of mind and official documentation of safety.

13. Radon Removal Duration in Ottawa and Similar Regions

Ottawa, Ontario, is one of Canada’s highest radon risk zones.

The Canadian Radiological Society estimates that 1 in 3 homes in Ottawa exceed recommended radon levels.

Because of Ottawa’s dense clay soil and cold winters, mitigation systems may take slightly longer — usually 6–10 hours for installation — due to deeper drilling and sealing requirements.

Local Timeline (Ottawa Region):

StageAverage Duration

Testing 2–7 days

Consultation 1–3 days

Installation 1 day

Post-Test 2–7 days

Total 1–2 weeks

14. Common Myths About Radon Removal Time

Let’s clear up some misconceptions:

❌ Myth 1: Radon removal takes weeks or months.

Truth: Most systems are installed in one day. Testing and verification take longer, but the removal itself is fast.

❌ Myth 2: You have to vacate your home during removal.

Truth: No need to leave. Technicians work in the basement or outside — your family can stay home.

❌ Myth 3: You can’t test right after installation.

Truth: Post-testing begins within 24 hours and usually finishes within 2–7 days.

❌ Myth 4: It’s the same as air duct cleaning.

Truth: Radon removal involves sub-slab depressurization — not cleaning ducts or filters. It’s a specialized, long-term system.

15. How to Speed Up the Radon Removal Process

If you’re eager to fix high radon fast, here’s how to shorten the timeline:

✅ Book certified professionals immediately after receiving test results.

✅ Prepare your basement (clear clutter, provide access to walls, sump pit, and foundation areas).

✅ Ask for combined testing + mitigation packages — saves days in scheduling.

✅ Schedule in off-peak seasons (spring or early fall) when contractors are less busy.

✅ Use continuous radon monitors for instant digital verification.