It is shown how the use of cross-correlation functions and their Fourier transforms provides a convenient probe of the division of the classical phase space for stretching vibrations of H2O into local, normal, and stochastic fractions. Resulting classical estimates for the numbers of total and local states, N(E) and Nl(E), respectively, as functions of energy are in excellent agreement with previous quantal and semiclassical results. The classical estimate of the number of stochastic states Ns(E) as a function of energy is a new result. The present method is readily generalizable to polyatomic molecules with many vibrational degrees of freedom.