As I said, in my post I already used bleach to sterilize the system. It took care of the smell. I have the hot water heater bypassed. I'm sure that the problem was my not purifying the system for the first couple of years. Now that problem is solved. I like the idea of adding a tiny bit of bleach to the water every time. Once I thought about it, I also use them fresh water to flush the toilet when I get to a site and don't want to hooked up to city water up right away. Sometimes it's raining or I arrive in the dark. Not really a problem .Thank you everybody for your input.