Radon testing
Professional air tests for the house you live in, placed and timed so the number means something
Open the radon testing pageWashington County · EPA Zone 1
Washington County is Zone 1. Your neighbor's kit is not your house.
The county map is not a reading for your bedroom. Neither is the kit from next door. If you're buying, the inspection clock is already running. If you already live here, the only number that counts is the one from the lowest room you actually use.
Zone 1 is a map
Washington and Sullivan Counties sit in the highest EPA band. Carter and Unicoi next door are Zone 2. We still put a device in the room.
A contract wants a time stamp
Closed house. Device off the floor. Continuous monitor when a realtor has to believe the file. A windowsill kit is not that.
Credentials you can look up
Tennessee does not issue a radon license. We work to NRPP and NRSB standards. Ask us for our certification ID.
Call (423) 455-9162
Or request a quote. Tell us the town, the foundation, and whether a contract is on the clock.
You're in the Ridge-and-Valley. The rock under Johnson City is folded limestone, dolomite, and shale. Some of that shale, including the Chattanooga, carries a little uranium. Uranium decays. Radon shows up. The EPA put Washington County in Zone 1 for a reason, and it put Carter and Unicoi in Zone 2 right next door. None of that is a reading for your bedroom.
We test the lowest lived-in level the way the protocol says: closed house, device off the floor, away from a supply vent. If you're buying, we run a continuous monitor so the file has a time stamp. If you already live here, a careful short-term test or a TDEC kit can be the first look. Then we talk mitigation only if the number earns it.
Mitigation around here is usually a sealed crawl membrane with a fan, or a pipe through a basement slab. Hillside houses toward Buffalo Mountain and Boones Creek often need both. We do not hang a bathroom fan in a foundation vent and call it a system.
Tennessee does not issue a state radon license. That's the law, not a loophole we hide. We work to NRPP and NRSB standards. Ask us for our certification ID and look it up. If you already have a number, start with radon mitigation cost in Johnson City, how long mitigation takes, or how to choose a mitigator in Tennessee. If you are buying, start with whether you need a radon test when buying a home in Johnson City. Zone 1 for homeowners is the map speech. Request a quote and tell us the town and the foundation.
What we do
Radon mitigation
Fan systems for crawls, slabs, and the split hillside basements this valley builds
Open the radon mitigation pageReal estate testing
Continuous monitors and written reports when a purchase contract is on the clock
Open the real estate testing pageWashington County radon risk explainer
This is a geology and housing guide, not a test result. It will not invent a pCi/L number for your address. Pick what you know. We will tell you what usually matters here, then you can request a real measurement.
Context only · not a radon reading
Washington County is EPA Zone 1
The EPA map puts Washington County in Zone 1, the highest predicted indoor-radon band (average screening above 4 pCi/L). That is a planning map from geology and older measurements, not a reading for your street. Carter and Unicoi next door are Zone 2. The line does not stop radon at the county sign. Test the house you actually sleep in.
Crawl space is the common Johnson City story
Most of the housing stock we see is a crawl over soil. Radon moves through that dirt, then through the floor and the return leaks. Mitigation is usually a sealed polyethylene membrane plus a fan that pulls from under the plastic (sub-membrane depressurization), not a box fan in a vent. Mid-century ranches around here usually sit on a crawl with a dirt floor and a few foundation vents that do not count as a mitigation system.
City water: the job is indoor air
If you are on Johnson City, Jonesborough, Kingsport, or Bristol utility water, the radon conversation is the air in the house. Utility water is treated and is not the usual indoor-radon driver here. Test the lowest lived-in level. Leave the geology map for context.
Living there: a careful kit or a professional test
If you just want a number, Tennessee's radon program will mail a free short-term kit. Follow the 3 to 5 day window and mail it back immediately. If you want us to place a monitor and write it up, request a quote. Either way, this tool will not invent a pCi/L reading for your address.
- Zone 1 here. Useful for why we take the county seriously. Useless as a substitute for a test.
- Expect a crawl-space membrane system if you mitigate, not a hardware-store fan in a vent.
- Utility water: skip the water scare. Book an air test in the lowest lived-in room.
- Occupied home: TDEC kit for a first look, or hire us to run a professional test.
Dedicated page: Washington County radon risk explainer. Buying against the map, not the rock: Zone 1 for homeowners.
Towns we serve
Johnson City, Kingsport, Bristol, and Jonesborough each have their own page.
Johnson City
Tree Streets crawls, Boones Creek slabs, Buffalo Mountain walkouts.
Jonesborough
Founded 1779. Stone, brick, and dirt crawls in the historic district.
Kingsport
Sullivan County Zone 1. Colonial Heights, Bloomingdale, Bays Mountain.
Bristol TN
Tennessee side of the split city. State Street, South Holston slopes.
Guides
The accordion is the short version. Buying a home, cost, timeline, credentials, Zone 1, crawl encapsulation, monitors versus kits, home value, walk-out spikes, test versus mitigate, the EPA 4.0 line, crawl versus slab, short-term versus long-term tests, mail kits versus a professional test, and the high-test handoff live on their own pages.
Buying a home in Johnson City
Test every purchase. Zone maps show county potential, not this address. Use the inspection contingency.
After a failed radon test
Elevated result, who pays in a Tennessee deal, crawl versus hillside, and the retest.
Zone 1 for homeowners
What EPA Zone 1 means in Johnson City and Washington County. County potential, not a test of one house.
Mitigation cost in Johnson City
Market ranges, what you are paying for, crawl versus slab, and how to get a real quote.
How long mitigation takes
Site visit, install day, same-day honesty, and the post-mitigation test window.
Choose a mitigator in Tennessee
No state radon license. Verify NRPP or NRSB. Ask us for our certification ID.
Does crawl encapsulation stop radon?
Plastic on a crawl is moisture work. Washington County still needs a test, and often suction under the membrane.
Continuous monitor vs kit
Kits screen fast. Continuous monitors show averages and night spikes common in East Tennessee walk-outs.
Does mitigation hurt home value?
A working system with a post-test usually helps a Johnson City sale. An unread high result is the deal risk.
Walk-out basement night spikes
Short night peaks are common. Decide from the longer average on the lowest lived-in floor, not one scary hour.
Test or mitigate radon first?
Test first. A Washington County map is not a reading. Clear results at or above 4.0 pCi/L mean plan mitigation, then retest.
What EPA 4.0 pCi/L means
4.0 pCi/L is the EPA fix line, not a safe-versus-unsafe cliff. Between 2.0 and 4.0, consider action after a valid Johnson City test.
Crawl space vs slab radon
Both foundation types can test high in Washington County. The foundation changes the system, not whether you should test.
Short-term vs long-term test
Short-term screens a decision this week. Long-term averages seasons. Start with the window your timeline actually needs.
Mail kit vs professional test
A careful mail kit can screen. Contract clocks and messy kit results are when a professional Johnson City test is the cleaner path.
Questions people ask first
Is Washington County really a high-radon county?+-
Highest predicted average radon potential for the county area, typically described as averages above 4 pCi/L. It is not your home's result. Sullivan County is Zone 1 too. Carter and Unicoi next door are Zone 2. Test the house.
Can I just use the free TDEC kit?+-
Yes, if you already live there and you want a first look. Order from the Tennessee Radon Program, run it 3 to 5 days, and mail it back immediately. If you're buying or selling, use a professional continuous test so the other side has a time-stamped report.
Does Tennessee license radon testers?+-
No. Tennessee does not issue a state radon measurement or mitigation license. TDEC points people to national credentials: NRPP and NRSB. Ask us for our certification ID and look it up on the directory. We do not print a number on this site because listings go stale.
What's the EPA action level?+-
4 pCi/L. EPA also says think about fixing between 2 and 4. We treat 3.8 and 4.2 as the same conversation. A 12 is a different one. We will not invent a number from your zip code.
Do crawl-space houses need a different system?+-
Usually yes. A dirt crawl gets a sealed membrane and a fan pulling from under the plastic. A basement or slab gets a pipe through the concrete. Hillside houses that have both often need both. A box fan in a foundation vent is not a system.
Should I test well water?+-
Test the air first. If you're on a private well or spring, especially in northern Washington County, a water sample can be a second step. City water in Johnson City, Jonesborough, Kingsport, or Bristol is not the usual indoor-radon driver. We will not guess a water number from a geology paper.
How fast can you test a house under contract?+-
A continuous monitor usually needs a closed house and about 48 hours on site, plus scheduling. Tell us the inspection window in the quote form. We will say if the calendar works. Do not wait until the last Wednesday on a split-foundation house.
Do you work Kingsport and Bristol, or only Johnson City?+-
Johnson City and Washington County first. We also cover Kingsport and Bristol TN (Sullivan County) and Jonesborough. Greeneville, Elizabethton, and Erwin when the drive makes sense. Say the town in the form.
What does mitigation usually cost?+-
Often about $800 to $2,500 for typical active soil depressurization. Many jobs cluster near $1,000 to $1,500. Complex foundations run higher. That is a market range, not a bid. Send the foundation and the test number if you have one.
How long does radon mitigation take?+-
Most straightforward systems in Johnson City go in about a day once we have seen the foundation. Count the site visit, design, install day, and a post-mitigation test after the house settles. Same-day from a cold call is not a promise for a split hillside or a house that needs electrical run.
How do I pick a radon mitigator in Tennessee?+-
Tennessee has no state radon license, so verify NRPP or NRSB in the public directory. A good quote names the foundation, the fan and sealing, electrical, a post-test, and a certification ID you can look up. Ask us for our certification ID.
Will this website tell me my radon level?+-
No. The Washington County risk explainer talks geology and housing. It will not print a fake pCi/L. The only reading we stand behind is a device in the room.
Same answers on a dedicated page: FAQ. Longer answers live on buying a home, mitigation cost, how long it takes, choosing a mitigator in Tennessee, after a failed radon test, and Zone 1 for homeowners.
Request a quote
Tell us the town, the foundation, and whether this is a home test or a real-estate deadline. Call or send the form.