They make 24v and 48v water pumps for buses and boats. Mine are 12vdc and is the Shurflo Whisper pump-I use two in parallel. When showering, I kick on both, then if someone uses a sink, you don't feel it. The Shurflo Whisper is of an older design using a mechanical pressure switch. I was at the Albuquerque Rally two years ago and the Shurflo factory rep said if you want dirt reliability-use the old style pumps. The newer high flow pumps are great when they work, but don't like any dirt getting into them. Personally-I'm going to use two of the Whisper pumps again on my truck conversion. Good Luck, TomC