Heating & energy
How to unblock a toilet or sink — and when to call a plumber
A blocked toilet is the most searched DIY problem in the UK, and most blockages clear in minutes with a plunger. Try these steps in order before you pay for a callout. If several fittings are slow, or sewage backs up, the problem is further down the drain and needs a professional.
Updated November 2026. Estimates based on typical UK prices.
What a plumber charges
£320 a day
Typical Midlands day rate from our rates data. Callouts for a simple blockage are usually much shorter than a day, and rates vary by region and time of day.
Be honest with yourself
Can you do this yourself?
You can do
- Plunging a toilet or sink
- Using a toilet auger
- Cleaning out a sink trap
- Preventing future blockages
Leave to a pro
- Blockages that return, or affect several fittings at once
- Sewage backing up or bubbling in other fittings
- Blocked outside drains or manholes
- Suspected collapsed or root-damaged pipes
The rules
Pipes inside your property boundary are generally your responsibility. Shared drains and the public sewer outside are usually the water company’s, so ring them if sewage is backing up from the street.
DIY guide
How to unblock a toilet or sink, step by step
Start with the simplest method and only move on if it does not work.
Tools you'll need
- Flange plunger (for toilets) and a cup plunger (for sinks)
- Toilet auger
- Rubber gloves and old towels
- Bucket
- Drain rods (for outdoor drains)
Materials
- Washing-up liquid
- Hot (not boiling) water
- Bicarbonate of soda and white vinegar (for slow sinks)
- 1
Stop flushing and protect the floor
Do not flush again, because it could overflow. Put towels and a bucket around the base, wear gloves and open a window.
- 2
Try hot water and washing-up liquid
Pour a good squirt of washing-up liquid into the bowl, wait a few minutes, then pour in a bucket of hot (not boiling) water from waist height. Boiling water can crack the porcelain.
- 3
Use a flange plunger
Press the plunger over the hole so it forms a seal, then push and pull firmly 10–15 times without breaking the seal, ending on a pull. If water drains away, flush gently to test.
Tip: A flange plunger (with a rubber sleeve) seals a toilet far better than a plain cup plunger.
- 4
Use a toilet auger if plunging fails
Feed the end of the auger into the bowl, turn the handle clockwise as you push to break up or hook the blockage, then pull it back and flush.
- 5
For a blocked sink: plunge and clear the trap
Remove standing water, block the overflow with a wet cloth, and plunge. If that fails, put a bucket under the U-bend, unscrew it by hand, and clear out the sludge and any debris.
Do not mix drain-cleaning chemicals. They can react dangerously and damage pipes.
- 6
Know when to call a plumber or the water company
If several fittings are slow or gurgling, water backs up in a shower when you flush, or sewage is rising in a manhole, the blockage is in the main drain. Stop using water and get a drainage specialist. Ask for a fixed price before they start.
- 7
Stop it happening again
Only flush toilet paper and human waste. Put wipes, cotton buds and sanitary products in the bin, even those labelled flushable, and keep fat and coffee grounds out of the sink.
Learn from others
Common mistakes to avoid
- Flushing again and flooding the bathroom
- Using boiling water on a porcelain toilet
- Mixing drain chemicals
- Using a cup plunger on a toilet instead of a flange plunger
- Ignoring slow drains until they block completely
Frequently asked questions
How do I unblock a toilet without a plunger?
Squirt a good amount of washing-up liquid into the bowl, wait a few minutes, then pour in a bucket of hot (not boiling) water from waist height. The soap lubricates the blockage and the water pushes it through. If that fails, use a toilet auger rather than anything improvised.
Why does my toilet keep blocking?
Usually it is too much toilet paper, or wipes and sanitary products, even those labelled flushable. A low-flush cistern, a partly blocked pipe or a problem further down the drain can also cause repeat blockages. If it keeps happening, call a plumber to check the pipes.
Can I use drain cleaner in a toilet?
It is best avoided. Chemical drain cleaners can splash, can damage some pipes and seals, and are dangerous if mixed or if you then have to plunge. Mechanical methods (plunger, auger) are safer and usually work.
Who is responsible for a blocked drain, me or the water company?
Pipes inside your property boundary, and those that only serve your home, are generally your responsibility. Shared drains and public sewers outside are usually the water company’s. If sewage is backing up from a manhole, ring your water company first.
How do I unblock a sink?
Plunge it with a cup plunger and the overflow blocked, then clear the U-bend trap under the sink into a bucket. Keep fat, coffee grounds and food scraps out of the sink to stop it happening again.
Ready to plan it?
Add this job to your renovation plan to get the order of work, who to book and a budget you can track.