We only use CG water supply (IF good water) to fill the fresh water tank, and disconnect..
All coach water usage is via the 12v pump from the fresh tank.
added a shower shutoff (got from Ace hardware) on the shower hose to conserve water usage.(Navy showers)
AquaHot(diesel) for heat and continuous hot water..
(112 fresh/115 gray/65 black tank capacities)
Your results may vary
SOB (some other brand)