Buyers of newer homes are often surprised to learn their house already has a radon pipe, and then surprised again when a test still comes back high. That is because many builders install a passive system that has no fan. This guide explains what a passive system is and how activation turns it into an active one.
Why does my new home with a radon pipe still test high?
Many new homes have a passive radon pipe that runs from under the slab to the roof without a fan. It relies on natural draft, which is often too weak to keep radon low. If a newer York home still tests high, a local contractor can activate the system by adding a fan, usually in the attic, then check suction and recommend a short-term retest after the fan has run at least a full day.
How Builders Install Passive Pipes
During construction, some builders lay a gravel layer under the basement slab and set a pipe into it before the concrete is poured. That pipe runs up through an interior wall and out through the roof. It is often labeled as a radon pipe where it is visible in the basement or utility room.
The idea is simple: warm air rising in the pipe creates a slight draft that pulls some soil gas from under the slab. It costs little to install while the house is being built, and it makes future mitigation much easier.
The catch is that natural draft varies with temperature and weather. On mild days, there may be almost no draft at all. That is why testing is still important in a new home with a passive pipe.
Signs Activation Is Needed
The clearest sign is a test result at or above 4 pCi/L. A result between 2 and 4 is also worth discussing with a contractor, since the EPA suggests considering mitigation in that range.
Test in the lowest lived in level with windows and doors closed. If the basement is unfinished but you plan to use it, testing there gives you useful information.
Before calling, look for the pipe. Check the basement or utility area for a labeled pipe coming out of the floor, and look in the attic for where it passes through on the way to the roof. Note whether there is an outlet or power nearby in the attic. These details help the contractor plan the activation and give you a more accurate quote.
What Activation Looks Like
Activation adds a fan to the existing pipe. The contractor first confirms the pipe really connects to the gravel under the slab and that its joints are sound. Then a section of pipe, usually in the attic, is replaced with an inline fan held by rubber couplings.
The fan needs power, so the contractor will plan an electrical connection near the fan. A U tube gauge is added lower on the pipe so you can check suction without climbing into the attic. Key slab openings, such as a sump, are sealed.
When the fan starts, the gauge should show suction. After at least a full day, run a short-term test. Most activated systems show a clear drop. If yours does not, the contractor can look for leaks or other adjustments.
Finish What the Builder Started
A passive pipe is a head start, not a finished system. If your newer York County home tests high, activation is often the simplest path. Knowing the steps ahead of time takes much of the stress out of the process. Call us and we will connect you with a local contractor who can check your pipe, add the fan, and guide your retest.
Frequently Asked Questions
Can I add the fan to a passive pipe myself?
Fan installation involves cutting the pipe, sealing couplings, and making an electrical connection, and the fan must be placed outside the living space with the exhaust above the roof. Most homeowners have a contractor do it so the system is installed and checked properly.
Does activating a passive system always work?
Most activations bring radon down significantly, but results depend on how well the pipe connects to the gravel under the slab and whether major openings are sealed. A retest after activation tells you whether the system needs any adjustment. The contractor can confirm the details for your home during the free on-site visit.
Should a new home with a passive pipe be tested?
Yes. A passive pipe alone does not mean low radon. Test the lowest lived in level after you move in, and again every couple of years. If the result is high, activation is usually the next step. The contractor can confirm the details for your home during the free on-site visit.