Remanufactured water pumps are rebuilt water pumps used in engines. More specifically, water pumps are pulley driven mechanisms that propel the coolant through the engine in order to keep it from overheating. Aftermarket companies tend to remanufacture older car parts to resell them instead of discarding them.
AutoZone, for example, has an in-house brand called Valuecraft, which rebuilds original equipment manufacturer components and resells them as remanufactured parts.
One way these parts companies come across core parts is to charge customers for broken parts, which places an additional amount on the new replacement part. This influences the consumer to return the core part for a partial refund to the original purchase price.