The white valve is your fresh water tank drain valve. If water comes out when you open it, it means that you are draining your fresh water tank, which you should do when you are not using the trailer for several weeks. Otherwise, keep it closed. When you are ready to drain all the water systems, probably in late Oct. or Nov. in your part of the country, you might have a service place look at it and open the valves for you if they are stuck. Other than that, go on your trip. You should have no problems with these valves.