My Master's degree is in water/waste water chemistry/civil engineering.
There is no practical way to ELIMINATE those water supply bacteria. No water system on the planet (that operates at reasonable cost) can do it. You can't either.
My suggestion to you is this: sanitize your RV water system a couple times a year, and run lots of water through it.
Use either chlorine bleach, or hydrogen peroxide (my preferred way) to sanitize, then use water freely. The smell develops when the water stagnates. It is a product of the anaerobic bacteria, perfectly normal, and to be expected. It will develop faster in water from a well or spring that is not treated with chlorine, partly because the chlorine knocks down (but does NOT sterilize) the bacteria level, and partly because the chlorine is an oxidizing agent that removes the sulfur.
