My 82 diesel K20 has factory water drain siphon hoses and valves on both tanks for water removal--they are fairly small though,so it would probably take a long time to drain it through them--mine are located near the front hanger for the rear springs. Other than that,you could siphon it out,or pessurize the tank with an air hose and let it blow out of the main fuel line to the engine into a gas can,or if you have an electric fuel pump you can hook it to the same line and let it run til its dry--my truck has an aftermarket electric pump,so all I'd have to do is disconnect the rubber line at the fuel filter and stick it in a can and run the pump--those little pumps will empty a 20 gallon tank in about 15 minites---another plus to having one is you can prime a new fuel filter with it--saves lots of cranking and bleeding to get it to fire up again.
P.S.Diesel is now 2.15 gallon here now,went up 40 cents in less than 3 weeks! I wouldnt just dispose of it--you could probably sell it,or put it in your home heating oil tank--too expensive to dump it!. /forums/images/graemlins/crazy.gif