One of my tenant raised up and issue that the ceiling above the partition is leaking. After checking, the water pump above the bathroom spoiled and caused the leaking. So contractor ask us to buy a pump and he will install it. Problem now is the owner himself don't know what type of the pump is in the unit and I have no idea what to browse.

The pump serves to provide high water pressure inside the unit in an apartment. Contractor himself I believe he also wanna avoid risk of buying wrong pump or involving himself in after sales service. So he asked me to buy the pump myself.
What kind of water pump that is common used, mostly won't have issue installing and suitable for apartment? Install above the plaster ceiling one