I know this may seem to obvious but do you have water flow even though the pump is running all of the time?
If you have no water than you have the drain valves open, remember you may have two sets of drain valves, aft and under the galley. If either of these are open, you will have plenty of pump action but no water.
If you you do have water flow while pump is running, you have leak or water pressure is not getting to full pessure. ( leak or pressure switch.
I have been to this school.