mosseater wrote:
I do our once a year after winter, then keep water in it all the time. If it sits for more than a few weeks or prolonged periods of rain, I change it out before the next trip. Our city water here has plenty of chlorine to keep the nasties at bay. When I change it, I also keep the valve open and try flush it out good before filling it up. Haven't had an issue in 6 years and I always have safe water in the trailer to use in case of emergency.
x2. Once a year works for us. My DW likes to carry bottled water for drinking and cooking.
I've never had a problem with nasty stuff in the water system.