A radon mitigation system, usually sub-slab depressurization, pulls radon gas from beneath your foundation through a sealed pipe and quiet inline fan, venting it above the roofline before it enters your home. In Plymouth County, most residential installs run $1,200 to $2,500, take one day, and drop levels below 2.0 pCi/L within 24 hours.
First, don't panic, and don't let anyone panic you into a same-day signature. A 12.0 reading feels alarming, but radon is a solved engineering problem. The fix is standard, proven, and permanent when it's installed right.
The system has a name that sounds worse than it is: active sub-slab depressurization. In plain English, we make the soil under your house exhale through a pipe instead of through your floor.
We look at your foundation type, slab condition, sump pits, crawlspaces, and where the soil gas is actually moving. This 30 minutes determines whether your system works or just decorates the basement.
A hole cored through the slab (or a sealed sump dome, or a membrane in a crawlspace), opening a small pit in the soil beneath.
Schedule 40 PVC from the suction point up through the house or along the exterior, exiting above the roofline. Routing is where craftsmanship shows: through a garage or closet chase when possible, tidy exterior runs when not.
A sealed inline fan, mounted in the attic or outside, never in living space. Modern fans hum at about the volume of a refrigerator and draw roughly 20 to 90 watts.
Major slab cracks, sump lids, and open joints get sealed so the system pulls from the soil, not your basement air.
A simple U-tube gauge on the pipe shows at a glance, forever, that the system is pulling. If those fluid levels ever even out, you call us.
48 to 96 hours after startup, a fresh test proves the number. That report is yours: keep it with the deed.
Fieldstone foundations in Chiltonville and older Kingston homes leak soil gas from a hundred joints, so sealing strategy matters as much as suction. Poured-slab ranches in North and West Plymouth are the textbook case: one suction point usually does it. Slab-on-grade construction in The Pinehills needs the sub-slab layout read carefully before coring. Raised ranches and splits in Marshfield and Pembroke often have finished lower levels the family lives in, which makes getting the number down more urgent, not less.
Sub-slab depressurization is the workhorse, but it's not the only tool, and matching the method to the foundation is most of the craft:
Sub-slab (the standard): for poured basements and slab-on-grade. One or more suction points through the concrete. This is 80% of Plymouth County installs.
Sump-pit systems: if your basement already has a sump, it's often the best suction point in the house. A sealed airtight dome converts the pit into the system's intake, keeping your water management intact underneath.
Sub-membrane (crawlspaces): dirt or gravel crawlspaces get a heavy-duty membrane sealed across the entire floor, with the suction pipe drawing from beneath it. Common in older Manomet and Cedarville cottages where additions sit over crawls.
Drain-tile systems: homes with interior perimeter drains can sometimes use the existing drain loop as the collection network, which means less coring and better coverage.
Mixed foundations, and Plymouth has plenty (a 1780s fieldstone core with a 1990s poured addition), often need two approaches on one house. That's a design question, not an upsell: one undersized system that misses half the footprint fails its retest and wastes everyone's time.
Thirty minutes, no obligation, and you'll know more about your house when we leave:
We map the foundation: footprint, slab condition, visible cracks, sump location, crawl access. We check where the run can go: interior chase through a garage or closet beats an exterior wall for looks and fan life, but not every layout allows it. We locate the electrical: the fan needs a circuit, and where that already exists affects price. And we talk about where the vent exits, because the code answer (above the roofline, away from windows) and the aesthetic answer (not front and center on your colonial) both matter.
You get the written number before we go. No pressure follow-up calls. A radon problem that waited forty years in your soil can wait a week for you to decide.
New England winter is when radon runs highest: a heated house pulls harder on the soil beneath it (the stack effect), and closed windows keep whatever enters. It's also a fine time to install. The work is mostly interior, systems perform identically in any season, and a January install means your highest-radon months are the ones already covered. If you tested high this winter, there's no reason to wait for spring.
Plenty of Plymouth County tests land between 4.0 and 6.0, and that band generates more hesitation than any other result. Here's the honest framework. The EPA's 4.0 line is an action threshold, not a cliff: risk scales with concentration and with hours of exposure, which means the same 4.8 reading is a different decision for a storage basement than for a finished lower level where your kid sleeps or you work all day. Ask two questions. Who spends time on the lowest level, and how many hours a week? If the answer is "the holiday decorations," monitoring and retesting seasonally is a defensible choice. If the answer is "people, daily," a system that takes the number from 4.8 to under 1.0 is the cheapest health-per-dollar purchase available to a homeowner, and it never needs to be decided again.
What we won't do is inflate a 4.8 into an emergency to close a sale. The number is the number; your household's use of the space is the judgment call, and it's yours. We'll give you the same recommendation we'd give a neighbor, which is where that framework came from.
$1,200 to $2,500 covers most single-system residential installs in this area. Toward the low end: accessible slab, short interior run, attic fan placement. Toward the high end: large footprints needing a second suction point, exterior runs on tall colonials, crawlspace membranes, or fieldstone sealing work. The quote is written, and the retest is in it.
$1,200 – $2,500
installed, single-system residential
Sub-slab systems have decades of track record. When a first configuration doesn't hit target, the fix is diagnostic: add a suction point, upsize the fan, seal further. The written quote states the target and the retest proves it.
Modern fans are close to silent inside the house. If you can hear it in your kitchen, something's installed wrong.
Roughly $100 to $250 a year at Massachusetts electric rates, depending on fan size. Think of it as a small appliance that never turns off.
Interior runs (through a garage or closet to the attic) last longer and look cleaner; exterior runs cost less up front. We'll tell you which your house wants and why in one sentence.
Five to ten years, typically. When it dies, it dies quietly, which is why the manometer matters. See radon system repair & fan replacement
Requirements vary by town for the electrical connection. We handle whatever Plymouth or your town requires as part of the job.
No. The state itself recommends hiring professionals certified by NRPP or NRSB, and DPH publishes a monthly list of certified pros. The certification belongs to the individual doing or overseeing the work, so ask for the person's credential, not just the company's.
Radon Mitigation for Plymouth and Plymouth County. Test it. Fix it. Prove it's fixed.
(508) 503-6186