What to Do If Your Septic Tank Is Backing Up: Emergency Steps

Few household emergencies are as distressing as sewage backing up into your bathroom or rising through your floor waste. If wastewater is bubbling up in your shower, gurgling in your toilet, or overflowing outside, you must take action immediately to protect your family’s health and minimise structural water damage.

Here is what you need to do right now, step-by-step.

During a heavy rainstorm in Singleton last spring, Chris noticed black, foul-smelling water rising through the laundry floor waste. Panicking, he tried flushing the toilet, which immediately caused wastewater to overflow the toilet bowl. He called our 24/7 emergency dispatch line. Our operator instructed him to isolate the main water supply valve and check his outdoor Overflow Relief Gully. Within 90 minutes, our vacuum truck arrived, pumped out 4,200 litres of waterlogged sewage, and cleared a tree root blockage at the tank inlet tee, restoring full drainage before carpets were contaminated.

Step 1: Stop All Water Usage Immediately

Every litre of water that goes down any drain in your house will immediately worsen the backup:

• Do NOT flush any toilets.
• Turn off all taps, showers, and baths.
• Cancel running dishwasher or washing machine cycles.
• If you have an automated water filtration or water softener system, switch it to bypass mode.

Step 2: Check Your Outside Overflow Relief Gully (ORG)

Go outside and inspect the grated drain located near your bathroom or laundry external wall:

• If sewage is spilling out of the outdoor ORG grate: The main line from the house to the septic tank or the septic tank itself is blocked/full. The ORG is working correctly by directing overflow outside rather than inside your home.
• If the outdoor ORG is completely dry but showers inside are backing up: The blockage is located inside your home’s internal drainage pipework between the fixtures and the ORG.

Step 3: What NOT to Do During a Septic Backup

• Do NOT pour chemical drain cleaners down the toilet: Caustic chemicals (sodium hydroxide or sulphuric acid) destroy beneficial bacteria inside your septic tank and will not unblock a full tank or submerged outlet.
• Do NOT plunge an overflowing toilet repeatedly: This forces contaminated sewage over bathroom tiles and into wall cavities.
• Do NOT open the septic tank lid yourself without safety gear: Septic tanks contain lethal concentrations of toxic gases (hydrogen sulphide and methane).

Sewage backing up in your home? Call (02) 4058 1923 right now for 24/7 emergency vacuum truck dispatch across the Hunter Valley.

Common Causes of Sudden Septic Backups

Learn more about rapid response services on our emergency septic service page.

Safe Clean-Up Protocol for Indoor Sewage Spills

If wastewater has entered your bathroom or laundry:

1. Wear Protective Gear: Put on rubber gloves, gumboots, and an N95 mask before entering the affected area.
2. Isolate Porous Materials: Discard contaminated bath mats, towels, and cardboard items in heavy-duty rubbish bags.
3. Disinfect Hard Surfaces: Wash tiles and waterproof surfaces with a solution of warm water and hospital-grade disinfectant or diluted household bleach (1 part bleach to 10 parts water).
4. Ventilate the Room: Open windows and use fans to circulate fresh air and dry floors rapidly.

Review our guide on signs your septic tank is full to prevent future backups.

Frequently Asked Questions

Is raw sewage backup covered by home insurance in NSW?

Most comprehensive Australian home insurance policies cover sudden and accidental wastewater escape, including professional biohazard cleaning and carpet restoration. However, damage caused by gradual neglect (such as not pumping out a septic tank for 8 years) may be excluded.

How quickly can an emergency pump truck arrive?

In urgent overflow scenarios across Maitland, Cessnock, and Singleton, we aim for same-day priority dispatch within 1 to 3 hours.

Can tree roots cause a sudden septic backup?

Yes. Invasive tree roots (especially from eucalyptus, willows, and fig trees) seek moisture and enter pipe joints between the house and the tank, creating severe physical blockages.

How much does an emergency pump-out cost?

Standard residential pump-outs cost $350 to $650 AUD, with an emergency callout fee of $150 to $300 AUD applicable for urgent after-hours dispatch.