In our tow vehicle/van conversion we regularly have two 5 gal jugs full of water for cooking related stuff + about 5 gallons of drinking water (+ assorted non-carbonated bottled drinks like green tea and v8 / etc) and get ~17 highway (chevy 1500 AWD high top van conversion). And in our 15 ft fiberglass trailer behind we fill the 15 gal fresh tank to balance the rig and give it some weight (fully loaded at ~2400lbs). While towing we get ~16 @ ~60mph.<br><br>When we run out of that...we fill the tanks from the river through a Katadyn Base Camp Gravity Filter. Endless supply at that point.<br><br><img rel="lightbox" src="http://www.fiberglassrv.com/forums/members/34081-albums922-picture4592.jpg" class="bbc_img">