Radon in Rockvale, Christiana, Eagleville and South Rutherford County

South and southwest of Murfreesboro, Rutherford County changes fast. Rockvale has become one of the county's quickest-growing areas, with new subdivisions replacing farmland along Highway 99. Christiana, south along Highway 231, mixes rural lots with new construction. Eagleville, in the far southwest near the Williamson and Bedford county lines, is a small town surrounded by farms. The whole county is EPA Radon Zone 1. This page covers what's specific to radon in these areas. We're a free referral service that connects homeowners with independent certified radon professionals.

Limestone close to the surface

Much of southern Rutherford County sits on the flat-lying Ordovician limestone of the Central Basin. In places, soil is thin and bedrock is near the surface; the cedar glades around Murfreesboro are the visible example. Elsewhere, thick red clay covers the rock. The USGS assessment for EPA Region 4 explains that residual clay soils formed on limestone can concentrate uranium and its decay products, and that karst features like fractures, solution channels and sinkholes give soil gas easy paths into foundations. Sinkholes and springs are a familiar part of the landscape in the south county. All of that adds up to radon potential that varies from lot to lot.

What the numbers show

The CDC's Environmental Public Health Tracking Network pools radon results reported by national labs. For Rutherford County, it shows 977 buildings tested from 2008 to 2017, a median of 1.5 pCi/L, and 15.3% of tests at or above the EPA's 4 pCi/L action level. Those are homes whose owners chose to test, not a random sample, but the spread is the point: a low median and a meaningful share of high results. Results aren't broken out by community, so a Rockvale subdivision and an Eagleville farmhouse rely on the same county picture. The only reliable number for a house is its own test.

New construction in Rockvale and Christiana

Most new homes here are built on crawl spaces or slabs. Neither Tennessee nor Rutherford County requires radon-resistant construction, so whether a new home has a passive radon pipe depends on the builder. If you're building or buying new:

• Ask whether the builder includes radon-resistant features: gravel or a venting mat under the slab, plastic sheeting, sealed openings and a vent pipe to the roof.
• Ask whether there's an electrical outlet in the attic near the pipe, so a fan can be added later.
• Test after you move in, even if a passive pipe is installed. The EPA says passive systems can reduce radon by about half; a fan does more.

See radon-resistant new construction for more.

Older farmhouses and additions

Older rural homes around Eagleville, Christiana and the Lascassas side of the county often combine an original crawl space or cellar, later additions and a slab porch or garage. A mitigator may need more than one suction point, or a crawl space membrane plus slab suction. Expect an on-site visit before a firm quote. Dirt-floor cellars and stone foundations need a sealed membrane, and gaps in old foundation walls make sealing harder.

Water

Most homes in the county are on public water, but some rural homes still use private wells or springs. Radon in Middle Tennessee well water is generally less of a concern than radon in the air, and the EPA says most radon risk from water comes from breathing radon released indoors. If you're on a private well, ask a water lab about testing.

Testing and permits

The Tennessee Radon Program, run by TDEC, sends one free short-term test kit per household, with lab analysis included. Request it online through TDEC's radon kit form. Electrical permits for Eagleville, Rockvale, Christiana and other unincorporated areas are State of Tennessee permits issued through Rutherford County's Building Codes Department; owners may buy one for work on their own home. See permits and licensing. Because these areas are farther from Murfreesboro, ask whether a mitigator's quote includes travel and the follow-up test.

Frequently asked questions

Do new homes in Rockvale have radon systems?

Some do. Tennessee and Rutherford County don't require radon-resistant construction, so it depends on the builder. Ask, and test after you move in either way.

Why does south Rutherford County have radon?

Limestone bedrock close to the surface, clay soils that can concentrate uranium decay products, and karst fractures and sinkholes that let soil gas move.

Who issues electrical permits in Eagleville?

Rutherford County Building Codes, as an issuing agent for the State of Tennessee's electrical program.

Should I test my well for radon in Rutherford County?

It's generally a smaller concern than radon in the air here, but if you use a private well or spring, ask a water lab. Test the air first.

Where this information comes from

• EPA Map of Radon Zones, county data (Rutherford County, TN: Zone 1)
• CDC Environmental Public Health Tracking Network, Radon Tests from Labs 2008-2017 (county summary via lung.com)
• USGS Open-File Report 93-292-D, Geologic Radon Potential of EPA Region 4 (includes Tennessee)
• EPA: Radon-Resistant Construction Basics and Techniques
• U.S. EPA, Consumer's Guide to Radon Reduction
• Tennessee Department of Environment and Conservation: Tennessee Radon Program
• Tennessee Radon Program free test kit request (TDEC)
• Rutherford County Building Codes, Electrical Permit
• Tennessee Department of Commerce & Insurance, Electrical Permits FAQ