Heavy rain can affect your septic system just as much as everyday use. When rainfall is well above normal, the extra water in the ground can stop your system from draining properly, and if it’s not managed, that can lead to backups inside your home.
Heavy rain saturates the ground around your septic system’s drain field. The drain field is where your system disposes of the treated effluent left over once wastewater has been processed inside your septic tank.
Normally, treated effluent flows from your septic tank, through the outlet, and out into the soil in your drain field, where natural processes safely return it to the environment.
Signs Your Septic System Is Struggling in Heavy Rain
- Toilets gurgling or draining slowly after flushing
- Toilets that won’t flush properly, or that back up
- Wastewater pooling on the ground near the drain field
- Bad odours around the tank or drain field after rain
- Sinks or showers draining slower than usual
When it rains heavily, the ground in your drain field can become so saturated that effluent can no longer drain into the soil correctly. This causes the septic tank to fill higher than normal, since the effluent has nowhere to go. If it continues, untreated waste can back up through the outlet and into the drain field, which is unpleasant, can smell, and can become a health hazard for you and your family.
That untreated waste can also clog the drain field’s pipes, so the problem doesn’t necessarily clear up once the rain stops and groundwater levels drop. The system can stay clogged until it’s properly serviced.
What to Do During Heavy Rain
1. Cut back on water use. Flush less often, use the half-flush option, and space out laundry and dishwasher loads.
2. Watch for warning signs. Gurgling drains, slow flushing or odours mean the system is under stress.
3. Book an early pump out if needed. If your tank is already close to due, having it pumped out before or during a wet spell reduces the load on the drain field and helps prevent permanent damage.
4. Don’t wait it out. A clogged drain field doesn’t always clear up once the rain stops. The longer it’s left, the more expensive the fix.
If you do need an earlier pump out, a compact truck matters more than people realise on a narrow driveway or when the ground is already wet. A smaller, lighter truck means less weight and less impact on your property, and with 90 metres of pump-out hose, we often don’t need to drive onto your yard at all.
Letting your drain field pipes clog with untreated sewage is an expensive problem to fix. Reducing the load on your system during wet weather is far cheaper than the repair.
About Paul Burgess
Paul Burgess is a licensed plumber and drainer with over 40 years of experience, and the owner-operator of Ward Septics. He has serviced septic systems across the Central Coast and Hunter Valley through countless wet seasons, and knows exactly how heavy rain affects a struggling system.
Worried About Your System?
NSW’s wet season can put real strain on a septic system that’s already due for a service. If you’re worried about your system, or it’s been a while since your last pump out, call 0438 315 514, or read more about our pump out service.
