I don't know if this applies to a 2008, but on my 1996, there is a valve just in front of where you hook up your water hose. You use this to fill up the fresh water tank, while hooked up. If this valve hasn't been closed, then you get no pressure to the taps & the situation you describe happens. So, search the water line from the hose hookup to where it all disappears into the van. If you find that valve (not the outside shower valves), then turn it to close & then try your taps. Hopefully this is all it is! I know i was very relieved to discover this as i had visions of replacing everything!!