  The distribution of electron density in the quantum Hall liquid is considered
in the presence of macroscopic density gradient caused by side electrodes or
inhomogeneous doping. In this case different Landau levels are occupied in
different regions of a sample. These regions are separated by incompressible
liquid. It is shown that the applicability of the approach by Chklovskii et al.
is substantially restricted if the density gradient is not very large and
disorder is important. Due to the fluctuations of the remote donor's density
the liquid in the transition region can not be considered as completely
incompressible. In the typical situation, when the gap between Landau levels is
not much larger than the energy of disorder, the transition region is a wide
band where electron density, averaged over the fluctuations, is independent of
magnetic field. The band is a random mixture of regions occupied by electrons
of upper level, by holes of lower level and by incompressible liquid. The width
of this band is calculated and an analytical expression for the fraction of
incompressible liquid in different parts of this band is given.
