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

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.

Please note: stand-alone radon testing services (without a home inspection) are offered in the greater Nashua area only.

NH Radon Testing

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.

NH Radon Testing

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 specifically), 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.

Radon House Entry

The Radon Decay Chain

NH Radon Testing
How radon is mitigated in NH.

How Is Radon Mitigated?

Thankfully, radon is easy to test for and usually fairly simple to mitigate, 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 to above the roof. This system works by removing the built-up pressure to prevent radon entry, and typically reduces indoor levels by up to 95%. Many newer homes are built with this pipe in place (without the fan, known as a “passive” mitigation system), so a fan can simply be added if more reduction is needed.


  • Price shown is valid when combined with a home inspection.
  • 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.

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

Sample Radon Report

Electronic radon testing NH

The Gate City Home Inspections Difference

Not all radon testing is equal. We utilize state-of-the-art professional electronic continuous radon monitors for our testing that are tamper-resistant. We provide a report at the end of the testing period that shows an hourly reading and an overall average. The best part: no waiting for a lab report! The results are ready immediately at the end of the test. A sample report can be viewed here. Whenever possible, we prefer to place the radon test in the home two days prior to the inspection, so the results will be ready at the inspection.

Quality Assurance

Our electronic continuous radon monitors (CRMs) are tamper-resistant and shipped back to the manufacturer annually to be recalibrated and tested. Approximately every tenth test performed with each device is done in tandem with a 2nd test as part of our quality control program to ensure continued accuracy.

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