[C320-list] Fresh Water Leak

[jim pasley]

OK. I give up. I need your help.
I just de-winterized Dream Weaver's fresh water system. Filled both tanks and an hour later, all the water is in the bilge. Here is what I have done so far.
1. Pulled the galley cabinet and checked every fitting for leaks with the system pressurized. No Leaks.
2. Check under the sink in the head. No leaks.
3. Checked the fittings at the shut off valves under the aft cabin. No leaks.
4. Checked the fittings connected to the tanks. No leak forward tank. Aft tank it looks like it is leaking a little so I pulled it loose and reinstalled with pipe tape and gasket sealer.

I then shut off the valve to the aft tank, opened the valve to the forward tank and pressurized the systen. It pumped up and shut off. I figured I would just run the forward tank. Went down to the boat after an hour and now the forward tank is empty and the bilge is full again. 
I give up!
With the forward tank valve open and the aft tank valve closed, can the forward tank still siphon into the aft tank? I am assuming I have a leak in the aft tank, but can't prove this is the case. 
This is a major leak. The front and aft tank will drain in less than an hour. There is no water in the forward section under the forward tank.
All the water seems to be flowing from the aft part of the boat, but I cannot find the source. Maybe one of you has run into this problem before. Any help would be greatly appreciated. Thanks.

Jim Pasley
Dream Weaver 691