Drive the RV to an authorized dump station -- typically found in campgrounds or at rest stops.
Put on the rubber gloves and go the rear left-hand side of the rig where most RVs have the black and gray water tanks and nozzle valves. Attach the dump station's dumping hose to the valve on the black water tank and turn it counter-clockwise to open the valves.
Turn the fresh water tank's valve counter-clockwise while the black water is pumped into the dump station holding tanks. Make sure the RV is parked over the drainage grate at the dump station before you open the fresh water tank valve, found on the underside of the rear panel.
Remove the dump station black water hose after the tank has drained and attach it to the RV's gray water valve, next to the black water tank valve. Turn the valve counter-clockwise and allow it to drain into the dump station tanks.
Remove the hose and place it back at the dump station's holding bracket. Turn all RV valves clockwise to lock them. Pour one cup of bleach into the black and gray water tank, and two tablespoons into the fresh water tank to prevent odors and mildew.
