  We study the stability of three-dimensional incompressible Weyl semimetals in
the presence of random quenched charge impurities. Combining numerical analysis
and scaling theory we show that in the presence of sufficiently weak randomness
(i) Weyl semimetal remains stable, while (ii) double-Weyl semimetal gives rise
to compressible diffusive metal where the mean density of states at zero energy
is finite. At stronger disorder, Weyl semimetal undergoes a quantum phase
transition and enter into a metallic phase. Mean density of states at zero
energy serves as the order parameter and displays single-parameter scaling
across such disorder driven quantum phase transition. We numerically determine
various exponents at the critical point, which appear to be insensitive to the
number of Weyl pairs. We also extract the extent of the quantum critical regime
in disordered Weyl semimetal and the phase diagram of dirty double Weyl
semimetal at finite energies.
