Our RV has only one inut connection, and a valve to determine if it goes to the lines, or to fill the tank. Problem is that the tank fill is only from a pressure line, such as a hose, and no way just to pour water in as some folks need. For us it is OK. All my connections use BRASS snap fittings, and we have a cannister filter with snap fittings that we can use or not depending. If you are in an area with high iron or other minerals, I would always use the filter inline from the source, and use that for tank filling, as well as daily use.