Easy way to find the water pump would be to back track the lines from the sink. They mount them in all kinds of areas on RV's. Under frig, under table seats, should be inside the livin area & not in a storage area.
2002 42' Monaco Signature Triple Crown tow 2014 F-150
2014 Voltage V3605 Sold 5/3/17
2012 F-350 6.7l CC 4X4, Sold 10/10/17