Septic tanks and flooding - HE1095
The full resource:
Information Sheet
During a flood, septic tanks and the drainage field may be flooded as well. This can clog up pipes which may cause a sewage backup (smelly black liquid) in toilets/drains. Other signs your septic tank may be affected include slow draining toilets and drains, and a smell of sewage.
If you’re a septic tank owner and experience any of the above, you will need to arrange a temporary or emergency toilet.
Septic tanks: What to do
- Check gully traps for debris and silt and remove material so that it is not flushed into the tank.
- Check outlet filters on the septic tank for clogging and clean or replace if necessary. Flooding of the tank will lift scum and fats that may block the outlet or outlet filter.
- Ensure stock cannot access the drainage field.
- Reduce water usage in your home until the septic tank system restores itself and the water table falls.
If you have concerns that the system has become damaged or clogged with silt or debris, we recommend that you have your septic tank and drainage field professionally checked and cleaned. Check online for septic tank contractors.
Important health tips
Wash and dry your hands, every time, after using the toilet, handling human waste or checking your septic tank system.
- Wet
- Soap
- Wash
- Rinse
- Dry
DO NOT:
- Use your septic tank system until the floodwaters over the drainage field have gone.
- Pump out your septic tank during flood conditions or saturated soil conditions as it may cause the tank to rise out of the ground, damaging the pipework.
- Attempt to clean out the septic tank yourself — tanks may contain dangerous gases. Find a septic tank contractor to clean the tank.
- Drive or operate heavy machinery over the drainage field as saturated soil is easily compacted — this will reduce the ability of the soil to absorb wastewater.
- Drink water from bores or wells close to flooded septic tank systems until the water has been tested and found to be safe.
For more information
- If you feel unwell contact your doctor or call Healthline for free 24/7 on 0800 611 116
- Keep listening to your radio for instructions, information and advice
- For instructions on making an emergency toilet, refer to: Protecting your health during and after a natural disaster