Q1:In heavy rain why does my tank overflow onto the garden? Roof water may be connected to the septic tank, heavy rain would cause the tank to overflow. This would result in suspended solids being washed into the percolation area which leads to blockages. If the inspector found that roof water was connected to your septic tank system this would be an automatic fail. Q2: What is a Percolation Area? A Percolation area is where the partially treated effluent from the septic tank is distributed to a network of perforated pipes laid in trenches usually located in your garden. the final treatment takes place when the effluent leaves the perforated … Continue reading Common Problems