Hi Margaret,

In most cases, radon entering the home through water is a small risk compared with radon entering your home from the soil.

The following was taken from the epa.gov website, hope it answers your question. Good luck! -- Bet

“If you've tested your private well and have a radon in water problem, it can be easily fixed. Your home's water supply can be treated in one of two ways; point-of-use or point-of-entry. Point-of-entry treatment for the whole home can effectively remove radon from the water before it enters your home's water distribution system. Point-of-entry treatment usually employs either granular activated carbon, or GAC, filters or aeration systems. While GAC filters usually cost less than aeration systems, filters can collect radioactivity and may require a special method of disposal. Both GAC filters and aeration systems have advantages and disadvantages that should be discussed with your state radon office or a water treatment professional. Point-of-use treatment devices remove radon from your water at the tap, but only treat a small portion of the water you use, such as the water you drink. Point-of-use devices are not effective in reducing the risk from breathing radon released into the air from all water used in the home.

For information on radon in water, testing and treatment, and radon in drinking water standards, or for general help, call your state radon office or visit www.epa.gov/safewater/radon.html. Your state radon office can assist you in obtaining radon-in-water test kits and interpreting test results.”

http://www.epa.gov/radon/pubs/consguid.html#radoninwater

Not something we test for, the testing here is for radon in the air.

I have never had any radon issues in my area.

Margaret... this is a new one on me. Fortunately, not. But if I did, I'd probably call in the radon remediation people first.

I have not dealt with this situation but I agree it can be remediated. 

Margaret Rome, Baltimore Maryland you got pretty good answers.

Yes, I had one where radon was really high. The buyer ended up installing a system that would 'purify' the water as it 'enters' the home! 

I had not heard of that before.  Not much radon problem in my area.