We applied the procedure developed by Prudente [Chem. Phys. Lett. 302, 249 (1999)] to compute the rovibrational energy levels of the water molecule. The procedure utilizes rotating wavefunctions as the trial basis in the correlation-function quantum Monte Carlo method. The procedure originally tested for a rotating harmonic oscillator and rotating Morse potential, has been extended for triatomic systems, replacing the spherical harmonics by the Wigner functions. We computed the rovibrational levels of the water molecule and compared the results with the experiment, and they are shown to be accurate.