How often do yall sanitize your fresh water tank?

CavemanCharlie wrote:

Your forgetting about the water tower. It is not pressurized.

Not forgetting, just don't know. I'm not a municipal water supply expert. For all I know the tanks easily could be under a slight pressure.

And I know for sure that some systems have open reservoirs as part of their "system" but I'm pretty sure that those are ahead of the treatment/filtering process. ;-)