Radon Extraction System: Terminology and SSD Guide
“Radon extraction system” is one of several terms homeowners encounter when researching radon. In practice, it refers to the same hardware as “radon mitigation system” or “sub-slab depressurization (SSD) system” — a continuously operating fan and pipe network that pulls radon gas out from beneath a building’s foundation slab before it can enter the living space. The terminology overlap can be confusing because contractors, manufacturers, and homeowner-education websites use the words interchangeably. This guide summarizes EPA and AARST guidance current as of 2026 and walks through what a radon extraction system is, how the terminology compares to other names, the standard SSD components, and what installation costs in 2026. Radon is a serious lung-cancer risk — consult your physician for symptoms and a NRPP-certified mitigation contractor for installation decisions.
What is a radon extraction system?
A radon extraction system is a powered ventilation system that draws radon gas from beneath a building foundation and discharges it outside above the roof line. The system operates 24 hours a day and is designed to reduce indoor radon concentrations to below the EPA action level of 4.0 pCi/L. The most common design — sub-slab depressurization — uses a 3- or 4-inch PVC pipe inserted through the basement slab into the gravel layer beneath, connected to an inline fan that creates negative pressure under the slab. Radon-laden soil gas is pulled into the pipe and vented through the roof. The fan runs continuously and typically lasts 8 to 10 years before replacement.
The radon testing in Colorado pillar covers the broader testing and mitigation context. The “extraction” terminology is a synonym that homeowners encounter on certain contractor websites — knowing it refers to standard mitigation hardware avoids confusion when comparing quotes.
Radon extraction vs radon mitigation: terminology distinction
The two terms describe the same physical system, but each appears more often in certain contexts. EPA, AARST (American Association of Radon Scientists and Technologists), and most state radon programs use “radon mitigation” as the standard term. Some private contractor websites use “radon extraction” because the term emphasizes the action (extracting gas) rather than the broader concept of mitigating risk. Both terms produce a working installation — the underlying hardware is identical.
Why “extraction” terminology persists
Extraction language is descriptive: the system literally extracts radon from beneath the slab. For homeowners hearing the term for the first time, “extraction” is more intuitive than “mitigation” or “sub-slab depressurization.” That intuitive clarity is why some contractors prefer the term in marketing materials, even though industry standards documents and certifications use “mitigation.”
Related terminology
- Sub-slab depressurization (SSD) — the technical name for the most common mitigation method
- Active soil depressurization (ASD) — broader category covering SSD plus drain-tile and sump-pit variants
- Radon mitigation system — the EPA-preferred general term
- Radon reduction system — another common synonym
- Radon ventilation system — sometimes used in older HUD documents
The cluster guide on what is a radon mitigation system walks through the standard terminology in more detail.
Components of a radon extraction system
A complete SSD installation consists of seven main components. AARST/ANSI Standard SGM-SF 2017 (and updates) specifies the design and installation requirements.
Suction pit and pipe penetration
The contractor cuts a 6- to 8-inch hole through the basement slab, removes about 5 gallons of gravel from beneath to create a suction pit, and seals a 3- or 4-inch PVC pipe into the hole. The pipe extends upward through the floor into the basement.
Sub-slab piping network
For larger basements or homes with multiple slab sections, additional suction points may be needed. Piping connects multiple points into a single header before reaching the fan.
Inline fan
A specialized radon fan (typically a centrifugal inline unit, 90 to 200 CFM) creates negative pressure in the sub-slab pipe network. Common brands include RadonAway, Festa, and AMG. The fan must be located outside the conditioned envelope — usually in the attic or on an exterior wall — to prevent any radon leak into living space.
Exhaust pipe to roof
From the fan, the pipe continues upward and discharges above the roof line. EPA-recommended discharge height is at least 10 feet above grade and 10 feet from any window or door that could allow re-entry.
U-tube manometer
A simple U-shaped clear plastic tube mounted on the visible pipe shows the pressure differential. The water column height confirms the fan is running properly. Homeowners check the manometer monthly; a sudden reading change indicates fan failure or system blockage.
Electrical connection
The fan is wired to a dedicated circuit (often a 15-amp branch) with a marked switch. The system runs 24/7 and typical power consumption is 70 to 150 watts per hour.
Slab and entry sealing
Any cracks in the basement slab, joints around floor drains, sump pits, and crawlspace access doors are sealed to prevent depressurization losses. Sealing alone does not solve radon, but it improves the effectiveness of the SSD system.
What a radon extraction system costs in 2026
- Standard SSD installation (single suction point) — $1,200 to $2,500 nationally
- Front Range installation (Denver metro) — typically $1,500 to $2,800
- Multi-point SSD (larger or split-foundation homes) — $2,500 to $4,500
- Crawlspace membrane and depressurization — $2,500 to $5,000
- Fan replacement after 8-10 years — $300 to $600 for fan plus $200 to $400 for labor
- Post-installation radon test — $100 to $200 (often included in installation contract)
- Annual electricity cost to run fan — $50 to $150 depending on utility rates
EPA action level and post-installation testing
EPA’s action level for residential radon is 4.0 pCi/L (picocuries per liter). Any home testing at or above 4.0 should mitigate; homes between 2.0 and 4.0 are also worth considering for mitigation per EPA guidance. After installation, a post-mitigation test (typically a 48-hour to 7-day measurement) confirms the system has reduced radon below action level. A well-designed SSD system typically achieves 50% to 95% reduction. The post-installation test result becomes part of the homeowner’s documentation.
How long a radon extraction system lasts
The PVC pipe and slab seal are designed to last the life of the home. The inline fan is the wear part — typical service life is 8 to 10 years. Some fans last longer; some fail earlier from condensation, debris, or electrical surge. The U-tube manometer makes failure detection easy. When a fan dies, replacement is a 1- to 2-hour service call from a NRPP-certified contractor. Many homeowners schedule a fresh radon test every 2 to 5 years even when the system appears to be running normally; conditions in the home change over time and confirming continued effectiveness is good practice.
Front Range radon extraction considerations
Colorado’s Front Range sits in EPA Radon Zone 1, the highest-risk geographic category. The Colorado Department of Public Health and Environment estimates that roughly half of Front Range homes test at or above the EPA action level. Sub-slab depressurization is the dominant mitigation approach because most homes have concrete basement or slab-on-grade foundations with gravel beneath. Crawlspace-only homes (less common but present in older Boulder and Denver neighborhoods) require membrane-and-depressurization systems instead. NRPP-certified mitigation contractors are abundant in Denver, Boulder, Colorado Springs, Fort Collins, and the broader metro; rural Front Range counties typically have one or two local providers plus traveling contractors from larger metros.
What makes a radon extraction system fail
Common failure patterns are well documented. Fan motor burnout (8 to 10 year service life). U-tube manometer dries out (rare but possible if the system was overhead-installed without proper fluid). Pipe blockage from debris pulled into the suction pit. Slab cracks that opened after installation, reducing system effectiveness. Inadequate suction point placement on larger homes that needed multiple points. Each failure mode is correctable, and the U-tube manometer is the single best early warning sign for most problems.
Hiring a NRPP-certified mitigation contractor
NRPP (National Radon Proficiency Program) certifies individuals and firms for radon measurement and mitigation. AARST (American Association of Radon Scientists and Technologists) operates the certification program. Verifying NRPP certification through the AARST online directory takes about thirty seconds and confirms the contractor has completed required training, passed the certification exam, and maintains continuing education. The cluster guide on professional radon test walks through how testing and mitigation contractors coordinate during the post-test installation decision.
Pre-mitigation diagnostic testing
Before installing the extraction system, a NRPP-certified contractor often performs diagnostic measurements to determine the best suction-point location. This includes a smoke-pencil test to map air leakage through the slab and a pressure-field extension test that uses a temporary vacuum to see how far the negative pressure propagates beneath the slab. The result tells the contractor whether one suction point is enough, or whether two or three are needed for full coverage. Skipping this step can result in an installation that reduces radon but not to below action level — particularly in larger homes with split foundation sections.
System design variants beyond standard SSD
While sub-slab depressurization handles most Front Range homes, several variants apply in specific situations. Drain-tile depressurization uses the existing perimeter drain tile (if present) as the suction network rather than cutting through the slab. Sump-pit depressurization seals the sump cover and converts the sump pit into the suction point. Submembrane depressurization is the standard approach for crawlspace foundations, where a sealed polyethylene membrane is installed over the dirt floor and depressurized from beneath. Each variant uses the same fan, manometer, and exhaust pipe; only the suction-point configuration changes.
Insurance and warranty considerations
Reputable mitigation contractors offer a labor warranty (typically 5 years) and a post-installation guarantee that the system will reduce radon below 4.0 pCi/L; if the first installation does not achieve that target, the contractor adds suction points at no additional cost until it does. Fan manufacturers typically offer 5-year warranties on the unit itself. Some homeowner insurance policies cover damage from radon-system component failure if it leads to water intrusion or other damage. Reviewing the contractor’s warranty document before signing is worth the few minutes it takes.
Maintaining a radon extraction system over time
Maintenance is light but not zero. Homeowners should glance at the U-tube manometer once a month to confirm the fan is still pulling negative pressure. The visible PVC pipe should be inspected annually for cracks or pulled-apart joints. The exhaust point above the roof should be checked for nest blockage during fall and spring. Snow accumulation around the discharge point is rarely a problem because the warm exhaust melts a clear column, but heavy ice can occasionally block discharge in extreme weather. Beyond these monthly and annual checks, the only scheduled maintenance is fan replacement every 8 to 10 years and a fresh radon test every 2 to 5 years to confirm continued effectiveness.
References
- EPA Radon Information — U.S. Environmental Protection Agency
- EPA Consumer’s Guide to Radon Reduction — U.S. Environmental Protection Agency
- CDPHE Radon Program — Colorado Department of Public Health and Environment
- CDC Radon Information — Centers for Disease Control and Prevention
Front Range homeowners weighing whether to install or service a radon extraction system can get in touch through our contact page for a referral to a NRPP-certified mitigation contractor near them.