The short answer
If one toilet won’t flush but other drains still work, the choke is usually in that toilet’s trap or the short branch to the property sewer — call a licensed plumber. If several fixtures won’t drain, or the overflow relief gully (ORG) outside is full of wastewater, stop using water and call McDermott Plumbing on (08) 6187 3999 or text 0406 882 648. Don’t tip drain chemicals down. If sewage is overflowing on the property or you already know the blockage is in Water Corporation’s sewer main, also call Water Corporation on 13 13 75 (24/7).
Do this first
- Stop flushing and stop using other toilets, showers and the washing machine if more than one fixture is slow or backing up. Extra water pushes sewage onto the floor or into the ORG.
- Look at the outdoor overflow relief gully (ORG) — the grated gully near an outside wall. If it’s full or overflowing with wastewater, the sewer on the property (or beyond) is under pressure. Stay clear and call.
- If only one toilet is blocked and the water level is stable, you can try a proper toilet plunger once or twice. Don’t force it if water starts rising elsewhere.
- Don’t tip caustic drain cleaners, “acid” openers or grease solvents into the bowl. They rarely clear a real sewer choke, can damage pipes and fittings, and make the job unsafe for whoever opens the line.
- Call (08) 6187 3999 or text 0406 882 648 with your suburb, whether one fixture or several are affected, and a photo of the ORG if it’s wet.
Your toilet, your drains, or Water Corporation’s main?
In the Perth metro scheme-sewered areas, wastewater blockages inside the property plumbing are the owner’s responsibility. Water Corporation looks after the sewer main (normally outside the property). If a plumber finds the choke in their main, they report it and Water Corporation clears their side — they publish a standard fee arrangement for plumbers who locate a blockage in the Corporation main.
A single blocked toilet with other drains still running usually means the pan trap, the S-bend, or the short branch into the property drain. That’s a plumbing job. Several toilets and wet areas failing together, or an ORG overflowing, points to a choke further down the property sewer — still usually the owner’s line until proven otherwise.
If wastewater is overflowing anywhere on the property, or damage is happening, Water Corporation says to call 13 13 75 immediately as well. We can still attend to clear or locate a property-side blockage once it’s safe.
Why toilets block in Perth homes
- Too much toilet paper, “flushable” wipes that aren’t, or sanitary products caught in the trap or bend.
- Kids’ toys, nappy liners or other foreign objects in the bowl.
- A choke further down in old clay property drains — tree roots at joints are common in established northern suburbs.
- Grease and soap from a laundry or kitchen line that shares the same branch, backing up into the nearest toilet.
- A partially collapsed or displaced pipe after ground movement or old age — less common, but it won’t clear with plunging alone.
What we do on a blocked toilet call-out
We work out whether it’s one fixture or the whole property sewer, clear what’s safe to clear, and tell you what we found. For a simple trap or branch choke that can mean plunging and a drain machine run. For a deeper property-line blockage we clear from the appropriate access point and check whether the ORG settles.
If the blockage sits in Water Corporation’s main, we report it so their crew can take over. You shouldn’t be left guessing who owns which bit of pipe.
We don’t quote prices on this page. On the phone or on site we’ll talk through the work before we start, and you’ll get an invoice that describes the cause — useful for landlords, strata and insurers.
When not to wait
- Sewage on the floor, in a bathtub, or coming up through a floor waste.
- ORG overflowing or wastewater pooling outside.
- More than one toilet or wet area failing at once.
- A rental with tenants unable to use the bathroom — say you’re the landlord or agent when you book.
Common questions
- Who do I call for a blocked toilet in Perth?
- Call a licensed plumber for blockages in the toilet or property drains. McDermott Plumbing: (08) 6187 3999 or text 0406 882 648. If sewage is overflowing on the property, or Water Corporation has already told you the blockage is in their sewer main, call Water Corporation on 13 13 75 as well.
- What is an overflow relief gully (ORG)?
- It’s the grated outdoor gully that lets sewer pressure escape outside instead of through your floor wastes and toilets. If the ORG is full or overflowing, stop using water and call a plumber — and 13 13 75 if wastewater is causing damage.
- Should I use drain cleaner in a blocked toilet?
- No. Chemical openers rarely fix a real sewer choke, can damage fittings, and make clearing the line more hazardous. Use a proper plunger once if only one toilet is affected, then call a plumber.
- Why won’t my toilet flush but the shower still drains?
- That usually means the choke is in that toilet’s trap or its short branch, not the whole house sewer. It’s still a plumbing job — plunging may help, but if the water keeps rising, stop and call.
- Do you clear blocked toilets at night?
- Yes. Emergency calls are taken 24/7. Call (08) 6187 3999 and we’ll give you an honest ETA for your suburb.
Related pages
Official sources
Last updated 30 September 2026. General information only. Every property is different, so call us to talk about yours.