The short answer
If only one toilet is blocked and the other sinks and drains in your home work normally, the blockage is usually in the toilet or the pipe just behind it, and a plumber can clear it. If several toilets, sinks and showers are slow or backing up at once, or water is rising in an outside drain, the blockage is in the main drain and you need a drainage company.
Toilet blockage or drain blockage?
| What you see | Where the problem is | Who to call |
|---|---|---|
| One toilet blocked, everything else fine | Toilet pan or waste pipe | Plumber |
| Toilet and nearby basin slow | Shared waste pipe inside | Plumber |
| Several toilets and drains slow at once | Main drain | Drainage company |
| Outside manhole or gully overflowing | Main or shared drain | Drainage company or water company |
What to try first
- Stop flushing. Each flush adds more water and can cause an overflow.
- Use a plunger. A proper toilet plunger with a flange works best. Push and pull firmly a few times.
- Try hot, not boiling, water. A bucket of hot water poured from waist height can break down soft blockages.
- Avoid harsh chemicals. They rarely clear solid blockages and can damage pipes.
When to call a plumber
Call a plumber if plunging does not work, if the toilet fills and drains very slowly, or if something solid has been flushed. A plumber can clear the pan and pipe, lift the toilet if needed, and check the flush and cistern. We clear blocked toilets, sinks, basins, baths and internal waste pipes. We do not carry out drain surveys or drain relining.
Is a blocked toilet the landlord's responsibility?
Landlords must keep drains and toilets in repair. If a fault causes the blockage, the landlord usually pays. If a tenant caused it by flushing wipes or other items, the landlord may ask the tenant to pay.
What does it cost?
MyJobQuote's 2026 figures put a London emergency plumber call-out at about £90 to £120. A plumber often clears simple toilet blockages within the first hour. We give a written price before starting.
Related service: blocked toilet and sink repair.
A few common questions
Should I call a plumber or a drainage company for a blocked toilet?expand_more
If only one toilet is blocked and other drains work, call a plumber. If several toilets, sinks and showers are slow at once, or an outside drain is overflowing, the problem is in the main drain and a drainage company is the better choice.
How do I unblock a toilet myself?expand_more
Stop flushing, then use a flanged toilet plunger with firm push and pull strokes. A bucket of hot, not boiling, water can help soften blockages. Avoid harsh chemicals. If the toilet still will not clear, or something solid was flushed, call a plumber.
How much does it cost to unblock a toilet in London?expand_more
MyJobQuote's 2026 figures put a London emergency plumber call-out at about £90 to £120, then £75 to £95 an hour. A plumber usually clears simple blockages within the first hour. Lifting the toilet or clearing a deeper pipe takes longer. Ask for a written price first.
Is a blocked toilet the landlord's responsibility?expand_more
Landlords must keep toilets and drains in repair, so blockages caused by faults are usually the landlord's to fix. If a tenant caused the blockage by flushing wipes, nappies or other items, the landlord may ask the tenant to pay. Check the tenancy agreement.
What should never be flushed down a toilet?expand_more
Only toilet paper and human waste should be flushed. Wet wipes, even those labelled flushable, nappies, sanitary products, cotton buds, kitchen roll and fat all cause blockages. Putting a small bin in the bathroom is the easiest way to prevent problems.