We provide a short proof that the dimensions of the mod p homology groups of the unordered configuration space B-k(T) of k points in a torus are the same as its Betti numbers for p>2 and k <= p. Hence the integral homology has no p-power torsion. The same argument works for the punctured genus g surface with g>0, thereby recovering a result of Brantner-Hahn-Knudsen via Lubin-Tate theory.