Why is their no resonance for H2O?

In chemistry, resonance or mesomerism[1] is a way of describing delocalized electrons within certain molecules or polyatomic ions where the bonding cannot be expressed by one single Lewis structure. A molecule or ion with such delocalized electrons is represented by several contributing structures[2] (also called resonance structures or canonical structures).

Each contributing structure can be represented by a Lewis structure, with only an integer number of covalent bonds between each pair of atoms within the structure.[3] Several Lewis structures are used collectively to describe the actual molecular structure, which is an approximate intermediate between the canonical forms called a resonance hybrid.[4] Contributing structures differ only in the position of electrons, not in the position of nuclei.
en.wikipedia.org/wiki/Resonance_(chemistry)

H2O only has single bonds, so that does not apply.