Key takeaways
- ✓ Raw sewage carries bacteria, viruses and protozoa that can cause serious illness, so treat any backup as contaminated and keep staff and customers well away.
- ✓ Sewage cleanup is not regular cleaning — professional teams remove the waste, discard what can't be saved, disinfect what can, and dry the area properly.
- ✓ Common causes include tree roots in pipes, grease build-up, wet wipes and other non-flushables, cracked or poorly jointed pipes, and soil movement around the property.
- ✓ Annual plumbing inspections, a pressure-reducing valve and sewer release valves all lower the risk of a backup.
- ✓ An area that isn't thoroughly cleaned, disinfected and dried remains a hazard to employees and visitors — and a breeding ground for mould and odour.
Why a sewage backup is more than a mess
A toilet that backs up or a floor waste that overflows is unpleasant in any building. In a commercial property it's worse: you have employees, customers and visitors moving through the space, and you have a business that can't trade until the area is safe again. When actual sewage is involved, what looks like a minor plumbing hiccup becomes a genuine biohazard.
Wastewater carries disease-causing bacteria, viruses and protozoa, and contact with it can cause illnesses such as gastroenteritis. That's why the safe assumption is simple: anything the sewage has touched is contaminated until it has been properly cleaned and disinfected — or discarded.
What to do first
- ✓ Close off the affected area immediately and keep staff, customers and visitors out.
- ✓ Stop using toilets, sinks and appliances that drain into the affected line.
- ✓ Switch off electrical appliances in the area, and cut power to the space if water has spread near outlets or equipment.
- ✓ Don't attempt to mop it up yourself — sewage cleanup needs protective equipment and proper disinfection, not a bucket and mop.
- ✓ Call a professional sewage cleaning company straight away. The faster the response, the less damage spreads and the sooner you're trading again.
If the overflow appears to come from the main wastewater network rather than your own plumbing, report it to Sydney Water on 13 90 90 as well.
What professional sewage cleanup involves
Cleaning up sewage isn't like regular commercial cleaning. Trained technicians work in full protective equipment and follow a decontamination process designed to make the space genuinely safe for re-occupancy, not just visibly clean. A professional crew will typically:
- ✓ Remove all sewage and contaminated water with purpose-built extraction equipment.
- ✓ Remove every item the backup has affected, and safely dispose of anything that can't be restored — saturated porous materials like carpet, underlay and cardboard usually have to go.
- ✓ Disinfect salvageable items properly, often off-site.
- ✓ Clean, disinfect and sanitise flooring and every surface in the affected area.
- ✓ Dry, dehumidify and ventilate the space so trapped moisture doesn't turn into a mould problem later.
Skipping or rushing any of these steps leaves an invisible hazard behind. If the site isn't cleaned, disinfected and dried thoroughly, it remains a health risk to your employees and anyone else entering the premises. For a closer look at what untreated sewage can do to the people in a building, see our guide to sewage backup health risks.
What causes sewage backups?
Understanding what triggers a backup is the first step to preventing the next one. The common culprits in commercial properties are:
- ✓ Tree roots that have grown into pipes and sewer lines in search of moisture.
- ✓ Grease and fat build-up — a particular risk anywhere with a commercial kitchen.
- ✓ Non-flushables — wet wipes, paper towel and sanitary items that bind together and block the line.
- ✓ Cracked pipes, faulty connections and poor joints in the plumbing system.
- ✓ Soil settlement around the property placing pressure on buried pipework.
- ✓ Irregular maintenance — small problems that were never inspected become big ones.
How to prevent the next one
No property is completely immune, but a few practical measures dramatically lower your risk:
- ✓ Book an annual inspection of your plumbing and sewer systems, and fix any faults immediately — a small repair now is far cheaper than a shutdown later.
- ✓ Install a water pressure-reducing valve to take stress off the system.
- ✓ Fit pop-up sewer release valves if your plumbing doesn't already have them.
- ✓ Keep fats, oils and wet wipes out of the drains — bin them instead, and make sure staff know why.
Need a hand in Sydney or Regional NSW?
One Prime responds 24/7 across Greater Sydney & Regional NSW. Our commercial sewage clean-up service covers extraction, deep cleaning, decontamination and drying — so your workplace is genuinely safe, not just tidy. Call 1300 774 631 or get in touch and we'll get your business back to normal fast.
Frequently asked questions
Can I clean up a sewage backup in my business myself?
It's not recommended. Sewage carries bacteria, viruses and parasites that can cause serious illness, and safe cleanup requires protective equipment, proper disinfection and controlled disposal of contaminated materials. Ordinary cleaning leaves invisible contamination behind. Close off the area and call a professional biohazard cleaning team instead.
How long will my business be closed after a sewage backup?
It depends on how far the sewage spread and what it touched. A contained overflow in one bathroom can often be cleaned, disinfected and dried within a day or two, while a backup that soaked carpeted or furnished areas takes longer because saturated porous materials must be removed and the space dried properly. A fast professional response is the single biggest factor in reopening sooner.
What usually causes sewage backups in commercial buildings?
The most common causes are tree roots growing into sewer lines, grease and fat build-up in the pipes, wet wipes and other non-flushable items, cracked or poorly jointed pipework, and soil movement putting pressure on buried pipes. Irregular maintenance lets small faults grow into blockages, which is why annual inspections are worth the cost.
Do I have to throw out everything the sewage touched?
Not everything, but the safe rule is to assume anything sewage touched is contaminated. Saturated porous items such as carpet, underlay, upholstered furniture and cardboard usually can't be adequately disinfected and should be discarded. Hard, non-porous items and surfaces can generally be cleaned, disinfected and kept.
Sources & further reading
- Sydney Water — Avoid wastewater overflows
- Better Health Channel — Sewage overflows at home
- HealthyWA — Domestic wastewater overflow
This article is general information, not medical or legal advice. Last reviewed 27 March 2019 by the One Prime Solutions team.