Water Softeners and Air Filtration Systems - Radon and Reverse Osmosis Filter

My brother lives in the southwest suburbs of Chicago in the Joliet, IL area where they do not get their water from the lake. He had been having water quality problems (stains, smells, spotted dishes, etc.) and had a professional come to his home to test his water.

This is where things sound a little fishy but I know nothing about water quality issues so I ask you guys/gals because my suspicions could be completely wrong........

He said the water tester guy came in, took a sample of tap water, and put a substance in the water that supposedly "attached" itself to impurities in the water and caused them to settle to the bottom. He dyed the water a yellowish color to make these imperfections visible to the eye. There were definite visible "impurities" in this sample.

After doing these tests, he told my brother that his town has 2000 foot deep wells because that's how far the town had to dig in his area to hit water. Due to these deep wells, radon was absorbed by the water and his house tap water had radon levels that were 100's of times higher than "guidelines." He then sold him a reverse osmosis filter for $5,000 installed that removes all radon and impurities.

Granted, my brother says his water is absolutely perfect now- the best he has ever seen anywhere he has ever lived. But what's the story with radon that seeps into the water, and does it take 5,000 bucks to install a reverse osmosis filtration system into a 4 bedroom/3 bath/3,500 sq. ft. home?

Thanks,
ualdriver

make sure he didn't have a whole house system installed for 5K........a 3500 gal a day pump R/O usually runs about 2500 installed......the story sounds believable though