I use to be the Bill of Material Manager for a huge Ford Authorized re-manufacturer.
Here is the list of parts for a water pump:
Casting
Impeller
Pulley hub
Bearing
Gasket
Box
Label
If your casting, pulley hub and impeller are good... the only two new parts are the bearing and gasket.
Sandblasting and a press are the only things required to rebuild the water pump. Know how and experience make a big difference too.
Most auto repair shops & auto parts stores can have them sent out for rebuilding.
Water pumps have the shortest Bill of Materials of all reman parts.
Things like brake shoes and disc pads have a longer parts list.
Engines have a very long list !
I was involved in that industry for 17 years and loved it. Loved some of the people and I help many, many people with older or obsolete parts often.
If they called and happened to get me or were transferred to me, they got what they wanted.
If they got the other guys/girls, they got told, Sorry, can't do it, not in the catalog or obsolete item.
I was a proud Car Guy, they were just doing a job.
Too bad some people don't care about what they do.
Good luck on the water pump JR,
Darren