Skip to content
Home/Radon Testing/Montgomery County/Rockville, MD
Radon testing
A continuous monitor on the lowest level that could be used regularly, read every hour for at least 48 hours. The written result comes the day we collect it.
4.9 rating, over 4,000 reviews NRSB-certified technicians Serving Montgomery County
A radon test in Rockville is $185, or $175 when it is added to a home inspection. That is the whole price: both visits, the monitor for the full 48 hours, and the written report with every hourly reading in it. The standard home-test price applies to a Twinbrook detached home, a planned-community townhouse or one individual Town Center residence; ask us to confirm scope and pricing for multiple units.
Day 1
Drop-off
A technician places it on the lowest level that could be used regularly, following EPA placement limits and the intended use of the space, inside a two-hour arrival window. With a home inspection, placement happens during the inspection visit.
48 hours
The house stays closed
For a short-term real-estate test, EPA guidance calls for closed-building conditions for at least 12 hours before the test and throughout the measurement. Windows stay closed, exterior doors open only for normal entry and exit, and the monitor logs hourly readings that help document the test conditions during the minimum 48-hour measurement.
Day 3
Pick-up and report
A technician picks the monitor up in another two-hour window and pulls the full record on the spot. The written report reaches you the same day.
NRSB-certified technicians. Our own team, certified by the National Radon Safety Board, not a subcontractor.
EPA testing guidance. Placement, closed-house conditions and the 48-hour minimum follow it, and your average is read against the EPA action level of 4.0 pCi/L.
Continuous monitors. Airthings Corentium Pro instruments, logging every hour for the whole test.
Appointment times are requests until our team confirms them. What the number means, how to prepare the property and the eight questions everyone asks are on the radon testing page; this page is about Rockville.
USGS mapped radon potential in Montgomery County using geology, soil and indoor-radon data. The City of Rockville advises that Montgomery County soil has high radon levels and recommends testing every County home. That background cannot supply the number for a Rockville address. A monitor at the property provides the result and creates the dated record required in covered sales and rentals.
The City's Comprehensive Master Plan describes Twinbrook as a predominantly single-family neighborhood developed in the 1940s and 1950s with small Cape Cod and rambler homes. West End is an older detached-home neighborhood. Town Center includes higher-density housing, while King Farm and Fallsgrove include detached homes, townhouses and apartment or condominium communities. Tell the technician how the lowest level could be used and who controls access. The individual layout determines where the monitor belongs.
Local background: City of Rockville radon requirements and guidance, City of Rockville Comprehensive Master Plan.
01
The City applies Montgomery County's rule to qualifying single-family home sales. The result must come from a test performed within one year before settlement and go to buyer and seller, but the code excludes condominium and cooperative units and lists several transfer exceptions.
02
Rockville's ordinance covers specified ground-contact or basement rental units and requires a result less than two years old at lease signing. Montgomery County has a separate three-year rule for its specified rental units. Check the property type and jurisdiction against each linked source.
03
EPA's real-estate guidance calls for the lowest level that could be used regularly, whether finished or unfinished. The technician also avoids closets, stairways, hallways, crawl spaces and enclosed areas with high humidity or strong air movement.
Where we test in Rockville, and what to tell us
Twinbrook, West End
The City documents Twinbrook's postwar Cape Cod and rambler housing and describes West End as an older detached-home neighborhood. State the lowest level that could be used regularly in the individual property and whether someone else controls access.
Rockville Town Center
The City documents higher-density housing in Town Center and plans additional housing near transit, jobs and amenities. For an existing residence, provide the unit location, the building entry process and the intended use of the lower levels.
King Farm, Fallsgrove
City plans record detached homes, townhouses and apartment or condominium communities in both areas. Tell the technician which type describes the address, how the lowest level could be used and who can provide entry for placement and collection.
We do not install radon systems, so we have nothing to gain from your number. If the result is at or above the EPA action level of 4.0 pCi/L, you choose who fixes it. Once the system is in, we can test again and tell you what it reads.
Rockville applies Montgomery County's pre-settlement radon testing rule to qualifying single-family home sales. The test must be performed within one year before settlement, the buyer and seller receive the result, and the County code lists property and transfer exceptions. Rockville also requires pre-lease testing for covered ground-contact or basement rental units, with a result less than two years old at lease signing. Facilities subject to an innkeeper's license are excluded from that City rental rule.
City of Rockville radon requirements; Montgomery County Code section 40-13C; Rockville Ordinance 06-23. Current as of September 2026. General information, not legal advice.
Qualifying single-family home sales do. Rockville applies Montgomery County section 40-13C, which covers detached and attached residential buildings but excludes condominium and cooperative units and lists several exempt transfers. The test must be performed within one year before settlement, with the result given to buyer and seller.
For a covered ground-contact or basement dwelling unit, Rockville requires testing before leasing and a result less than two years old at lease signing. The City ordinance excludes facilities subject to an innkeeper's license, so landlords should check the property's exact category against Ordinance 06-23.
No. Montgomery County section 29-35E uses a three-year period for its specified ground-contact or basement rental units, while Rockville's municipal ordinance uses a two-year period for its covered units. Confirm which City and County requirements apply to the property before relying on an existing report.
The technician uses the lowest level that could be occupied regularly and applies EPA placement limits. Describe the individual layout and intended use when requesting the appointment, since Twinbrook's Cape Cod and rambler homes do not all present the same testing space.
Book online or call (703) 450-6398.
Schedule a radon test Request a price
NextDay Inspect
46179 Westlake Dr, Ste 200, Sterling, VA 20165
(703) 450-6398
