  We consider a Schr\"odinger operator with bounded, measurable potential in
multidimensional Euclidean space. We prove for every $L^2$-eigenfunction a
quantitative equidistribution estimate. It compares the total $L^2$-norm with
the $L^2$-norm over an equidistributed collection of balls. Our estimate is
explicit with respect to the radius of the balls, norm of the potential and the
energy of the eigenfunction. Similar estimates also hold for Weyl sequences and
for linear combinations of eigenfunctions, as long as the associated
eigenvalues are sufficiently close.
