TDiRoy ...
Roy, you didn't mention what yr & model your driving...So I'll tell you how to do a 99 Golf TDI water seperator drain.
With the hood open and you are standing infront of the eng compartment, look directly down onto the top of the fuel filter assembly. You will see a phillips screw between and slighly below the fuel lines. Using a #2 phillips screwdriver losen this screw abouty 3 -4 turns and you can lift the filter assembly up & out of the retainer. It a slighty snug lift up it will come up enough for you to access the drain on the bottom of the fuel filter. Placing a small catch can under the filter assembly ...you can then turn open the drain valve. With the drain open you can draw off about 3-4 oz. of fuel. Then close the drain, and examine the fuel sample for signs of water. If you see small globules of water ( Which I seriously doubt you will find any)....continue draining untill you have a clean sample. IF every thing looks good after the first sampl draw....simply wipe any excess fuel from the body of the filter assembly and reinstall. Slip the filter back into the retainer and tighten the phillips screw. Your Done.
If for some odd reason you do have a water issue, drain the filter assembly, re-install the filter assembly, and then you will have to prime the filter assembly if it is empty. Simply remove the fuel line coming from the filter ( its the line that is clear plastic tubing) and using something to draw a vacume you will suck fuel back into the filter to refill it.
I doubt that you will find this step nessassery because so far water has not been a common problem....do the sample check...re-install the filter..then start your car....there is enough fuel in the filter to run the eng. and it will refill by it self...you're all done.
