About every six months to a year I add about 2 to 3 cups of Chlorox to my tank while I am filling it so it gets mixed pretty good.

I then open all taps until I get a strong smell of chlorine from each, including the shower and toilet.

I let it sit for about 1/2 hour, drain everything, and then refill with fresh water. I then run water through all taps again to flush the lines. I also change filter elements when I do this.

I have no idea if this is the way to do it, but I do know that it is likely going to kill any bugs that are in the system. Despite "sanitizing" like this we still bring water from home that we know is pure for coffee and ice cubes, etc.