Do the gullies (at ground level) fill and overflow when it rains?
Clear any leaves above the grid. If it is still full of water then there is most likely either something blocking the trap (sometimes the trap is a U-bend) underneath the grid or some problem with any underground pipes that take the water away. Make sure the pipes run freely so water runs away rather than rising up the walls. Roof leaks – High winds may have dislodged tiles or lifted lead work, so get these checked if anything looks amiss from the ground (it may help to use binoculars). Tiny holes or cracks in leadwork can admit quite a lot of water and are difficult to see even close up. Sometimes, if this is possible, a trip into the roof-space can help pin-point a leak. Flat roofs – Don’t forget these, all outlets should be clear so that if they get piled up with snow it can melt away safely. Under-floor Vents – Leaves may have mounded up over ventilating grilles to under-floor spaces. Clear leaves and soil away from these grilles to maintain ventilation to protect the underside of
