Does Marion County Well Water Carry Radon? What Florida Geology Means for Your Home
Marion County's limestone aquifer can dissolve radon into your well water. Learn what levels matter, how to test, and how to fix it for good.
Your Ocala well water might be serving up something invisible that came straight out of the Floridan Aquifer's ancient limestone—and most homeowners have never once thought to check for it.
Radon gets plenty of press as an indoor-air issue, but in Marion County the conversation needs to include your water supply. Here's why, and what you can actually do about it.
Why Florida's Geology Makes This a Real Conversation
Marion County sits squarely over the Upper Floridan Aquifer, one of the most productive limestone aquifer systems on Earth. That same porous, ancient limestone that gives Ocala its legendary springs also contains trace amounts of uranium and radium—naturally occurring elements left over from geological time.
As groundwater percolates through limestone, it dissolves radon gas produced by radium decay. By the time that water reaches your well pump and comes out of your kitchen tap, it can carry measurable radon concentrations.
This isn't a scare tactic—it's basic hydrogeology. The USGS and Florida Department of Health have documented elevated radon in Florida groundwater for decades. The question is never "could it be in my water?" but "how much is actually in mine?"
What the Numbers Actually Look Like
Florida well water radon levels vary widely depending on local geology, well depth, and aquifer zone. Here's a realistic reference range:
| Radon Level (pCi/L in water) | What It Means |
|---|---|
| < 100 pCi/L | Below EPA's stricter proposed MCL; low concern |
| 100–300 pCi/L | Near the proposed 300 pCi/L MCL; worth monitoring |
| 300–1,000 pCi/L | Above stricter threshold; treatment recommended |
| 1,000–4,000 pCi/L | Meaningful contribution to indoor air; treat promptly |
| > 4,000 pCi/L | Exceeds alternative MCL; high priority for treatment |
Marion County homes tested through state programs have returned results across this entire spectrum. A house in Silver Springs Shores on a 200-foot well isn't guaranteed to read the same as one in Dunnellon tapping a shallower zone. The only way to know where your home lands is to test your specific well.
The Indoor Air Connection
Here's the part that surprises most homeowners: waterborne radon doesn't just stay in your drinking water. When you run a hot shower, wash dishes, or run the washing machine, dissolved radon degasses into your indoor air.
The standard engineering conversion: every 10,000 pCi/L of radon in water contributes roughly 1 pCi/L to indoor air. That ratio means water-borne radon is a secondary but real pathway to elevated indoor air levels—especially in smaller or tightly sealed Florida homes where the bathroom and laundry room aren't well-ventilated.
If you've already tested your indoor air and found elevated radon, your well water deserves a look as a contributing source.
How to Test for Radon in Well Water
Radon in water requires a separate, specific test—your standard 5-panel or 10-panel well water test does not include it. You have two practical routes:
- State-certified laboratory test – A water sample is collected and sent to an accredited lab. Results typically take 5–10 business days. Cost: $75–$150.
- Professional on-site sampling – A water treatment professional collects the sample correctly (radon is volatile; improper collection invalidates results) and submits it for you.
Don't attempt to grab a sample in any open container—radon escapes quickly. Proper sample collection uses a closed-fill method with no air bubbles. Our free water testing service can walk you through the process or handle it for you.
Treatment Options That Actually Work
If your test comes back elevated, there are two proven technologies:
Aeration (Air Stripping) Water is sprayed or agitated to allow radon gas to escape before the water enters your home's plumbing. Very effective—can remove 95–99% of dissolved radon. The released gas is vented outdoors. Installed cost for a Marion County home: $2,500–$5,000.
Granular Activated Carbon (GAC) Tank A large carbon media tank installed at the point of entry adsorbs radon from the water. Effective, but the tank itself becomes mildly radioactive over time and requires periodic proper disposal of spent media. Generally more practical for lower radon concentrations. Installed cost: $1,500–$3,500.
For most Marion County homes with confirmed elevated radon, aeration is the preferred long-term solution because it removes the gas rather than accumulating it. A properly sized system requires knowing your well's flow rate and peak demand—this isn't a one-size-fits-all calculation.
Both options work best as part of a broader well water treatment plan, since Marion County wells often have co-occurring issues like iron, hardness, or hydrogen sulfide that benefit from whole-house treatment at the same time.
Other Well Water Issues to Test Alongside Radon
While you're testing, it's worth running a comprehensive panel. Marion County well water frequently presents with:
- Iron and manganese – staining, metallic taste (see iron & sulfur removal)
- Hardness – scale buildup, shortened appliance life (see water softener installation)
- Hydrogen sulfide – rotten-egg odor, common in the aquifer zones around Ocala and Belleview
- Nitrates – relevant for homes near agricultural land in rural Marion County
Bundling a radon test with a full water quality panel saves time and gives you a complete picture before investing in any treatment equipment.
The Bottom Line for Marion County Homeowners
Radon in well water is a real, geology-driven issue in this part of Florida—not a theoretical one. The Floridan Aquifer's limestone is the reason Marion County has world-class springs and the reason some residents have elevated radon in their taps. Those two facts come from the same source.
The good news: it's testable, it's treatable, and the treatment systems are reliable and reasonably priced. What you shouldn't do is assume your water is fine without data.
Ready to find out what's actually in your well? Schedule a free water test with Ocala Water Treatment and we'll put real numbers behind the conversation. Explore our full range of water treatment services or learn more about well water treatment options specific to Marion County's aquifer conditions.