Water overflowing from a manhole or gully is a sign of a blocked drain. Gullies can be cleared by hand or you can hire a power hose. If it still does not drain away smoothly, locate the blockage by raising the drain manhole covers. If you can see the blockage, remove it; otherwise, you'll need to hire a set of drain rods. Screw two or three together and insert the end into the flooded manhole. Feel for the half channel at the base and push the rod into the drain, turning it clockwise at the same time, in the direction of the blockage. Screw on more rods as required until the blockage is encountered and dislodged.