You should be able to see the water in the bottom of the bowl. The water is heavier than the diesel, and will sink to the bottom. It usually looks different from the diesel and is easily recognizable.
If you see anything other than diesel in the bottom of the bowl, then, as stated previously, drain it out using the screw in the bottom of the bowl.
Bleeding is not usually necessary after draining the water / trash from the bowl.
Be sure to hold some type of container below the filter bowl before turning it to catch the fuel / water / trash coming out.