We also dry camp most of the time. We carry a 50 gallon, potable water tank in the bed of the truck. I did it with the 3/4 ton short bed and now have a long box dually. I installed a water tap at one end and connect a double male camping hose to that and then from the pump into the tank fill. I used to use the compressor and use air pressure to make the water go from the outside tank into the 5er. Now I use a 12 volt pump that moves water pretty fast. I just pull up next to the 5er and hook up the cables to the house batteries. The pump has an on/off switch. The tank itself is one of those you might pick up at farm and fleet type store. It's the white plastic one. I have also used a blue 45 gallon barrel and used the compressor to pump the water. When we were new at camping, some 35 years ago, we had a hard top camper and had 14, 5 gallon containers that we stuffed into any spare space we had. I also used a small 12 volt air compressor to move the water, with some renovations to the jugs. Those were the days.......
I'm not sure but those that have to have use pressure to fill their potable water tanks might be able to use the type of water pump we have. The pump I have is a Bur Cam(www.burcam.com
), model # 300209c. It can pump 350 gph depending on the distance. It's a Canadian made pump but you can get the idea if you have a look at their site. Anyway I hope you get the idea.