The percolation area should be able to cope with the normal outflow from your septic tank plus normal rainfall, but in times of heavy rain, this might be put under stress. There are various factors involved. Too much rain water in the water table will eventually cause water-logging. In the worst case, treated effluent may seep to the surface. The percolation area may not be working properly, pipes clogged or too small an area to handle the volume of water. Drainage of water may not be sufficient. If you are seeing any flooding around your percolation area, we will be happy to advise on best course of action.
My garden is water-logged around the percolation area after heavy rain. What can I do?