What Does a Radon Mitigation System Actually Look Like?
A 3" or 4" white PVC pipe, a quiet inline fan, and a tiny pressure gauge. That's it. Here's what each part does and what it looks like in a real Maine home.
Done well, a radon mitigation system is a single white PVC pipe routing from your basement floor to above your roofline, with a quiet inline fan in an unconditioned space (garage, attic, or exterior wall) and a small U-tube pressure gauge near the fan. That's the whole system.
The Four Components
| Component | What it looks like | Where it lives |
|---|---|---|
| Suction point | A 5" hole cut through your basement slab, sealed around a vertical 3" or 4" PVC pipe with polyurethane. | Basement floor — usually in a corner, utility room, or behind the furnace. |
| PVC pipe | White or gray Schedule 40 PVC, 3" or 4" diameter, glued joints. Runs vertically from slab to above roof. | Routes through closets, mechanical chases, garage, or up an exterior wall depending on your floor plan. |
| Fan | A small cylindrical inline fan, roughly the size of a coffee can, with two PVC ports. White or black housing. | Must be installed in an unconditioned space — garage, attic, exterior wall mount. Never inside living space (per EPA & ASTM standards). |
| U-tube manometer | A small clear plastic tube about the size of a dollar bill, with red liquid showing pressure differential. | Mounted on the pipe in your basement. Lets you verify the system is running at a glance. |
The Three Common Pipe Routes
Every house is different. These are the three main ways the pipe gets from your basement to above the roofline.
Interior Route
Pipe runs up through closets, plumbing chases, or the garage and exits through the roof. Pros: Pipe and fan are protected from Maine winters; no exterior pipe visible from the street. Cons: Requires more in-home routing through finished spaces.
Exterior Route
Pipe exits the rim joist horizontally, runs up the side of the house, with the fan mounted high on the exterior wall. Pros: No interior routing through finished spaces; easier on retrofit. Cons: Pipe is visible from outside; we paint it to match siding to minimize this.
Attached Garage Route
For homes with attached garages, pipe routes through the garage to either an attic fan location or up through the garage roof. Pros: Often the cleanest install — fan in unheated space, almost no visible pipe in living areas.
What a System Should Not Look Like
❌ Fan in a basement
EPA and ASTM standards require the fan to be downstream of all living space. A fan inside the home means any small leak in the pipe pushes radon-laden air into your living area.
❌ Pipe terminating below the roofline
Discharge must be above the roof and 10 feet from any window or air intake. A pipe that ends at the soffit or under the deck just relocates the problem.
❌ No manometer or labeling
You should be able to verify the system is working without specialized tools. A working manometer plus a system label (with installer info and install date) is required by ASTM standards.
❌ Audibly loud fan
A correctly-sized, properly-mounted fan is barely audible from inside the home. Loud humming usually means the fan is undersized for the system, mounted with too much vibration coupling, or the resonance is amplifying through pipe straps.
See Real Maine Installs
Our gallery shows actual finished systems we've installed across central Maine.
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