To provide a water supply apparatus that can be inexpensively installed irrespective of the number of electrodes.

The water supply apparatus having pumps 7-1 and 7-2 for supplying water in a water receiving tank 4 to a demand side, and level detection means 3-1 and 3-2 for detecting levels in the water receiving tank includes: a storage part for storing a plurality of level control patterns corresponding to the number of levels detected by the level detection means, a decision means for deciding a level control pattern stored in the storage part, and a pump control means for rotatively driving the pumps in accordance with the level control pattern decided by the decision means and the levels detected by the level detection means.