30% of nh homes have elevated radon

It's odorless and invisible. And it could kill you.

If the lowest level of the home you’re purchasing has a concrete slab floor, we recommend adding Radon Gas testing to your home inspection. According to a 23-year NH Department of Health & Human Services study, more than 30% of NH homes tested for radon have elevated concentrations above 4.0 pCi/L, the EPA’s recommended action level. For an additional fee, we’ll place an electronic continuous radon monitor in the home for a minimum of 48 hours to record the radon level hourly during the testing period and provide a report at the end of the test. Testing is the only way to detect the presence and level of radon gas, which has no odor and is invisible to the naked eye.


What is radon?

Radon is a radioactive gas known to cause over 20,000 deaths from lung cancer annually. Radon gas is released by radium as part of the “decay chain” that occurs as the unstable element uranium decays into other elements in the soil and rock. As a gas, some of the radon decays in the open air, producing progeny that are radioisotopes of heavy metals that readily attach to other airborne particles (such as dust) making them easily inhaled. These radioactive particles are then free to attach to lung tissue which can cause cancer with enough exposure.


How does it enter the house?

Typically when a home is built, a concrete slab is installed as the basement floor. If there happens to be an ample amount of uranium under the home (or radium, more directly), radon, as a gas, can become trapped and build up pressure beneath the slab and behind the foundation walls. It then leaks into the home through every small crack and hole and becomes trapped in the home. Outside, the radon is free to dissipate into the open air, but inside this leads to an elevated level in the home.


How is radon mitigated?

Thankfully, radon is easy to test for and usually fairly simple to mitigate. Most mitigation in this area is done through a process known as “sub-slab depressurization”, or “active” mitigation. A hole is placed in the concrete slab floor of the basement, where a PVC pipe is installed and sealed. This pipe is typically run to the exterior, where an inline fan is installed. A pipe is then run from the fan up above the roof. This system works by preventing the built-up pressure that causes radon entry and typically reduces indoor levels by up to 95%. Many newer homes are built with this pipe already in place (without the fan, known as a “passive” mitigation system), so a fan can simply be added if more reduction is needed.


Annual Deaths in the USA

Home Fires
Drunk Driving

The Radon Decay Chain



Uranium 238

Thorium 234

Protactinum 234

Uranium 234

Thorium 230

Radium 226

4.47 Billion Years

24.1 Days

1.18 Minutes

245,500 Years

75,400 Years

1,600 Years

Common elements in soil and rock.

Radon 222

3.82 Days

Present in the atmosphere.

Polonium 218

Lead 214

Bismuth 214

Polonium 214

3.05 Minutes

26.8 Minutes

19.7 Minutes

0.16 Minutes

Short-lived radon progeny. The radioactive decay particles that can be inhaled and cause lung cancer.

Lead 210

Bismuth 210

Polonium 210

22 Years

5 Days

138 Days

Long-lived radon progeny. The heavier-than-air particles that can't easily be inhaled.

Lead 206



Radon Gas Testing

  • 48-hour active test done with state-of-the-art, tamper-resistant electronic continuous radon monitor, performed by a certified inspector holding AARST/NRPP membership.
  • Full radon report with hourly readings delivered electronically at the end of the test period – no waiting for the lab.
  • Price shown is valid when combined with a home inspection.

*Stand-alone radon testing services without a home inspection offered in greater Nashua only. Call for pricing.

Scroll to Top