  We prove that a foliation $(M, F)$ of codimension $q$ on a
$n$-dimen\-sio\-nal pseudo-Riemannian manifold is pseudo-Riemannian if and only
if any geodesic that is orthogonal at one point to a leaf is orthogonal to
every leaf it intersects. We show that on the graph $G = G(F)$ of a
pseudo-Riemannian foliation there exists a unique pseudo-Riemannian metric such
that canonical projections are pse\-u\-do-Rieman\-ni\-an submersions and the
fibres of different projections are orthogonal at common points. Relatively
this metric the induced foliation $(G,\mathbb{F})$ on the graph is
pseudo-Riemannian and the structure of the leaves of $(G,\mathbb{F})$ is
described. Special attention is given to the structure of graphs of
transversally (geodesically) complete pseudo-Riemannian foliations and totally
geodesic pseudo-Riemannian ones.
