The Mitigation Installation Process

A guide to understanding the radon mitigation system installation process
​Radon mitigation is a construction project, and a well‑designed system should be installed with care, transparency, and adherence to national ANSI/AARST standards. Knowing what to expect helps you feel confident, ask the right questions, and ensure the system installed in your home matches the design you approved.
1. ​Before the Contractor Arrives
​A professional radon mitigator should:
  • Confirm the appointment time and expected duration.
  • Review the final design and fan model with you.
  • Explain where equipment will be located.
  • Identify any areas of the home they will need access to
  • Discuss safety considerations (combustion appliances, electrical access, etc.)
​Why it matters:
​Clear communication prevents surprises and ensures the installation follows the contract you signed—not an improvised design.
2. ​Arrival and Setup
​When the contractor arrives, you should expect:
  • A brief walkthrough of the planned system
  • Verification of suction point locations
  • Confirmation of pipe routing and discharge placement
  • Protection of work areas (drop cloths, shoe covers, etc.)
  • Safe handling of tools and materials
Why it matters:
​A professional setup signals that the contractor is following a planned design rather than making decisions on the fly.
 3. System Installation
A standard sub‑slab depressurization system typically includes:
​Creating the Suction Point(s)
  • Drilling through the slab or accessing the crawlspace.
  • Excavating a small pit beneath the slab to improve airflow
  • Sealing the penetration around the pipe
​Installing the Piping
  • Running PVC pipe from the suction point to the fan
  • Routing through the garage, attic, exterior, or mechanical room
  • Securing the pipe with proper supports
​Mounting the Radon Fan
  • Installing the fan in an approved location (attic, garage, or exterior)
  • Ensuring the fan is accessible for future replacement.
  • Wiring the fan to a dedicated or appropriate electrical source
​Discharge Placement
  • Venting above the roofline
  • Ensuring the discharge is away from windows, soffits, and openings.
  • Following ANSI/AARST clearance requirements
​Why it matters:
​Proper routing and discharge placement are essential for long‑term performance and safety.
4. Sealing and System Integrity
​The contractor should seal:
  • Slab cracks
  • Utility penetrations
  • Sump lids
  • Crawlspace barriers
​Why it matters:
​Sealing improves system efficiency and reduces the amount of air the fan must move to depressurize the soil.
 5. System Labeling and Safety Features
​A compliant system includes:
  • A U‑tube manometer or digital indicator
  • Labels on all visible pipe runs.
  • A fan label with model and serial number
  • An electrical disconnect or service switch.
  • A radon system information label near the manometer
​Why it matters:
​These features help you monitor the system and ensure future technicians understand its design.
6. Post‑Mitigation Testing
​A certified technician should perform a continuous radon monitor (CRM) test after installation.
​You should receive:
  • A written test report
  • An explanation of the results
  • Confirmation that the system is achieving acceptable radon levels.
​Why it matters:
​Post‑mitigation testing is required by national standards and verifies that the system is working as intended.
7. Final Walkthrough
​Before leaving, the contractor should:
  • Show you how to read the manometer.
  • Explain what normal operation looks like
  • Review warranty terms.
  • Provide system documentation.
  • Confirm that the installation matches the contract.
​Why it matters:
​A final walkthrough ensures you understand your system and have everything you need for long‑term peace of mind.
8. Payment
​​ Make your final payment only after you receive a certified post‑mitigation radon test result showing the system is performing at or below the level guaranteed in your contract.
Most guarantees specify either the contractor’s stated performance level or the national mitigation threshold of 4.0 pCi/L.
​If the post‑mitigation result is higher than expected, the contractor should return to diagnose and correct the issue before payment is due. Once the confirmed test result meets the guaranteed level, the system has fulfilled its performance requirement and final payment is appropriate.
Why it matters:
​Radon mitigation is one of the few home services where the quality of the work cannot be evaluated at the moment the contractor leaves. The system’s effectiveness is proven only through a certified post‑mitigation test.
​Requiring payment after receiving the test result:
  • ensures the system is actually reducing radon to safe, standards‑based levels
  • protects you from paying for a system that does not meet the promised performance
  • aligns the contractor’s incentives with proper diagnostics and installation
  • reinforces the national standard that mitigation is complete only when radon levels are verified
​This step gives homeowners confidence, creates accountability, and ensures the mitigation process ends with a clear, measurable outcome.