You have a responsibility, as far as reasonably practicable, to prevent surface water running off your property onto, or across, the highway.
Such run-off may cause flooding or icing so creating a source of danger to the public.
You must not allow water from gutters or down pipes to discharge onto the surface of the highway, either directly or by leakage - closed grids can be used within footways in these circumstances. Gutters and down pipes must be regularly checked and kept in good repair.