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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 all of Howard County
Schedule a radon test Call (703) 450-6398 Find your community
Three communities in the county have pages of their own with local detail. The test, the price and the technicians are the same everywhere in the county, so you can also book straight from here.
Howard County identifies Columbia as an unincorporated planned community whose New Town zoning district was created in 1965 and includes about 31,600 homes.
In Elkridge, Howard County says Elk Ridge Landing became the largest colonial seaport north of Annapolis in the late 1700s.
Howard County says Ellicott City Historic District is both on the National Register and a local historic district.
A complete Ellicott City address is needed because postal labels near the Patapsco do not by themselves establish the county.
A radon test in Howard County 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 amount applies to one residence. Investor packages, multiple rentals or several transaction addresses need a confirmed scope and price.
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 Howard County.
Howard County appears in EPA Zone 1, its higher estimated potential category. The map cannot turn Columbia's planned-community history or Ellicott City's district context into a household reading. Measure the selected residence for its actual result.
Columbia, Elkridge and Ellicott City each have a local link from the Howard County page. Provide the full property address, the residence or unit and the lowest level that could be used regularly. List additional units or buildings separately if the request extends beyond one residence.
Local background: EPA Map of Radon Zones raw county data, EPA Map of Radon Zones guidance, Columbia local source, Ellicott City local source, Elkridge local source.
01
Howard's Zone 1 classification signals higher estimated area potential. A Columbia, Elkridge or Ellicott City household still needs its own indoor data before making a property decision.
02
Allow for pretest preparation, monitor placement, the complete 48-hour collection and pickup when setting a transaction deadline.
03
Movers, painters or contractors can affect doors, windows and device security. Choose a quieter period or discuss the activity before setup.
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.
Maryland's residential disclosure framework includes radon among the hazardous or regulated materials covered by an owner's actual knowledge for certain single-family residential property of four or fewer units. The statute has enumerated exemptions and does not itself require a radon test. County and municipal requirements may differ, so check the rules for the property's location and type before relying on an existing result.
Md. Real Property section 10-702. Current as of September 2026. General information, not legal advice.
EPA assigns the county its highest potential category, but the map has no address-level resolution. The Howard home result comes from the monitor placed inside it.
Columbia, Elkridge and Ellicott City are linked from this county hub. Use the full street address near a county boundary, then choose the matching local page. The county's Zone 1 background remains an area category rather than a substitute for an indoor measurement.
Placement considers the lowest level that could be used regularly. Explain whether a lower room is occupied now, planned for later use or separate from the requested residence. The technician selects the compliant indoor location.
Their activity can affect access, doors, windows and mechanical operation, so disclose the schedule before placement. If the work cannot preserve closed conditions or protect the monitor, choose a quieter period. Report any unexpected disturbance instead of trying to fix the data afterward.
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
