A water sprayer includes a handle having a passage, a housing having a pathway and a chamber communicating with the passage and a passageway communicating with the chamber and the pathway of the housing, to form a valve seat between the passageway and the pathway of the housing. A stem is rotatably and slidably received in the passageway and the chamber of the housing, and includes a block having a groove for selectively communicating with the passage of the handle. The block includes a channel formed by a swelling and having an opening selectively communicating with the pathway of the housing when the stem is rotated relative to the housing, to control a water flowing through the housing.