Filling fresh water while dry camping

I purchased a 35 gallon water tank that I keep in the bed of my pick-up (trailer camper, and truck has a shell). I fill the water tank and then I can transfer the water to the trailer using a simple, non expensive water transfer pump I purchased from Lowes. The pump is 120v AC, and this works great when we are at campsites that has electricity but no water on the site. But I also have a 400 watt inverter (battery 12v DC to 120 AC household current). I keep a lightweight extension cord in my truck. I plug in the inverter, plug in the extension cord, plug in the pump and let the water fill the trailer. Works absolutely marvelous. And yes, I use it mostly with AC power available, but have on several occasions also used it powering from the truck battery. What's so great about this set up, it's 100% portable! I can take water anywhere.