I can't picture how big that boat is, but I'd suspect there's only one fresh water pump... so if you have pressure at one tap (galley sink?) and not another (forward sink, aft shower) I'd probably look for disconnected lines first.
Another test might be with the shore water hookup and with the onboard freshwater pump turned off; does water flow to the forward sink and aft shower? If not, another reason to suspect disconnected lines.
Accumulation of fresh water in a bilge
-- pump to disconnected line -- might be another symptom.