When a private well draws groundwater through radon-bearing granite, the gas dissolves in the water and releases into household air during showers, dishwashing, and laundry. Aeration systems strip radon from well water before it enters the house, typically removing 92 to 99% of it. In the Plymouth area, installed aeration systems generally run $3,000 to $6,500.
If your home is on town water, skip this page. If you're on a private well in South Plymouth, Carver, Plympton, Halifax, or the rural edges of Kingston and Duxbury, keep reading, because your water can be a radon delivery system.
Groundwater moving through granite picks up dissolved radon. Every hot shower, every dishwasher cycle, every laundry load then releases it into your air, right in the rooms where your family spends time. The EPA's rule of thumb: roughly 10,000 pCi/L in water contributes about 1.0 pCi/L to indoor air. Massachusetts sets its own water guideline at that same 10,000 pCi/L mark, a separate benchmark from the air-contribution ratio, and wells in granite country can test in the tens of thousands.
This is also why some homes mitigate their air, retest, and still see stubborn numbers: the slab system is working, and the water is restocking the air. If you're on a well, test both. Always both.
A proper radon-in-water sample tells you the concentration. No number, no system. A radon-only water analysis runs $150 to $200 with results in about a week. If you're testing the well anyway, comprehensive panels that bundle radon with bacteria, metals, and other contaminants run roughly $500 through a state-certified lab and take two to three weeks.
Water from the well feeds a sealed tank where air is bubbled through it aggressively. Radon leaves the water for the air phase, exactly as it does in your shower, except here it happens inside a controlled tank.
That radon-rich air pipes up and out above the roofline, same principle as a slab system.
A pump restores household pressure downstream, so your fixtures never know the difference.
Water sampled after install proves the removal. Report in writing.
Aeration is the EPA-preferred method for meaningful concentrations because it removes the gas rather than collecting it. Granular activated carbon (GAC) tanks exist as a budget path for lower concentrations, with a real caveat: the carbon accumulates radioactivity over time and needs annual servicing, and eventually becomes a disposal question. We'll tell you honestly which side of that line your number sits on.
Straightforward residential aeration installs typically land between $3,000 and $6,500, aligned with the state DPH's published typical range on the low end. But here's the honest truth about water treatment pricing, straight from how the best companies in this region actually operate: nobody serious quotes a system before seeing your water chemistry. Iron, manganese, sediment, and your radon concentration all change the design, and pretreatment needs can add real money. That's why the water test comes first, always: your number and your chemistry set the price, and any company quoting a firm figure before the lab report is guessing with your money.
Simpler than the air side: a sample drawn correctly (aeration during collection skews results low, so technique matters), sealed, and lab-analyzed. The radon-only analysis comes back in about a week; a comprehensive panel takes longer. If you're already doing an air test, adding the water sample to the same visit is the efficient move, and it's the only way to see your full radon picture in one report.
These systems are reliable, not invisible. What ownership actually looks like:
The blower runs when water runs, adding a modest electrical cost you'll barely notice next to a well pump. An annual look-over checks the spray heads or diffuser for mineral buildup: Plymouth County well water often carries iron and manganese, and heavy mineral loads sometimes want a pre-filter ahead of the aerator to keep it clean. The vent stays clear the same way your slab-system vent does. And a retest every couple of years confirms the removal rate is holding.
Budget a service visit annually and you'll likely go years between actual problems. What you should not do is install and forget for a decade: a fouled aerator degrades quietly, exactly like a dead radon fan.
Point-of-use filters (under the kitchen sink) miss the entire mechanism of waterborne radon risk. The exposure isn't the glass you drink; it's the gas released by every hot-water fixture in the house, with the shower as the main event. Treatment has to happen where the water enters the home, before it reaches any fixture. That's why aeration systems are whole-house by design, and why a sink filter marketed for radon is solving the wrong problem.
$3,000 – $6,500
aeration system installed
If you're on a well in this geology, a water test is cheap certainty. Fine air today doesn't rule out high water, especially if usage patterns change.
No. Softeners handle minerals, UV handles bacteria. Radon removal needs aeration or GAC specifically.
Inhalation is the dominant risk: the gas your water releases into household air. Ingestion risk exists but is secondary. That's why the fix targets the air pathway via the water source.
They're separate systems solving separate pathways, often on the same house in Carver and Plympton. When both are needed, we design and price them together.
Radon Mitigation for Plymouth and Plymouth County. Test it. Fix it. Prove it's fixed.
(508) 503-6186