Since any water stored in a tank should by ultra safe regulations be considered as less than potable quality then all potable water sources have to be direct from the mains and thus ( unless a pressure reducer is fitted ) all potable water will be at mains pressure. Or is there an alternative. Perhaps cold water storage tanks with UV anti bacteria lighting.Try and use some alternative thinking FFS.
Water from water bowsers for emergency supplies has to be potable ( not harmful ) but need not be wholesome ( maybe adverse in taste and / or appearance )