You may have a stuck check valve at the water inlet or all your faucet valves and screens may be filled up with scale which prevents water from coming out. Also check to see if you have a bypass on the water heater. Sediment has a tendency to settle in my bypass hose over time and clogs it. I have to disconnect the hose and run a coathanger through it to clear the sediment out. I need to add a brass check valve to prevent this from occuring.
'01 2500hd ext. cab, 8.1 litre gas, 5 sp. Allison auto
3.73 rear end
Mag-Hytec rear diff cover
Amsoil Dual by-pass oil filtration system
Amsoil synthetics all around
265 watt AM Solar, Inc. system