If your property has a septic tank, heavy rain and flooding can affect its ability to treat wastewater from your home. When rainwater or floodwaters pond over the trench area, there is nowhere for the effluent to drain because the trenches and soil beneath are saturated causing the system to fail.
When trenches are saturated, contaminants from the partially treated wastewater can enter ground and surface water. In addition, when the water can’t flow out of the septic tank into the trenches it can easily back up into bathrooms and laundries.
Before the flood
A well-maintained septic system is better able to cope with heavy rains or flooding, so it is strongly recommended that you have your tanks pumped out regularly (every 3-5 years) and maintain your trench areas by keeping the grass well mowed. In the event of an impending flood, seal the lid and inspection openings with silicone to keep excess water out of your septic tank.
During the flood
If possible, don’t use the septic system as the soil is saturated and the surrounding area is flooded. If the trench area becomes covered in water, stay well away and don’t allow children or pets to play in the water as it may be contaminated with raw sewage.
Under flood conditions do not have your septic pumped out as the surrounding saturated soil may cause it to ‘pop out’ of the ground.
After the flood
Have your tank inspected by a professional if you suspect that your septic has become damaged. Most septics are not damaged by flooding as they are below ground, however the outlet and trenches can become clogged with silt and require cleaning by a professional.
If needed, have the septic tank pumped out once the flood waters have receded and the trenches have started to dry out to help remove any silt and debris which may have washed into the system.
If sewage has backed up into the house, clean the area and disinfect the floor ensuring that you wear rubber gloves. Use a disinfectant such as chlorine bleach or similar to disinfect the area thoroughly.