In water, the central atom, oxygen has two bond pairs and two lone pairs. Thus, it should have a bent shape (please comment if you have any doubts regarding this). The bond angle should be 109.5 degrees, but the bond angle decreases due to repulsion between lone pairs and bond pair-lone pair repulsion.
Note - To understand this answer, you should be clear in the basics of VSEPR theory. If you have any doubts, ask in the comments.