New To This Forum.. Questions in Welcome To The Oliver Travel Trailer Forums Posted May 25, 2008 Hey, beeser ! We use the water stop valve to save water when showering because we mostly boondock. The valve lets you wet down and with one quick click, turn the shower head off without changing the temperature settings. Then after soaping down, one click lets you rinse quickly off with the water still set at the just right temperature. I'll bet that this clever bunch on these forums have found other uses for the valve though ! Now you really have me confused. Just to be sure we're talking about the same thing, I was referring to the valve that is controlled by a T-type handle in the bathroom. Does this control fresh water or drain water?