Signs to look for
- The button or lever moves but nothing happens
- The lever feels loose or the button has sunk and stays down
- A weak flush that does not clear the pan
- The cistern stays empty or takes a very long time to refill
What to do first
Lift the lid and look
Carefully lift the cistern lid and put it somewhere safe. Is there water in it? If yes, the problem is the flush mechanism. If no, water is not getting in.
If the cistern is empty
Check the isolating valve on the pipe feeding it. The screwdriver slot should line up with the pipe. Check that cold water is reaching other taps too.
If the cistern is full
Note whether the button or lever is connected to anything when you press it. Photograph the mechanism so whoever repairs it knows what to bring.
Flush by hand if you need to
Pouring a bucket of water into the pan can clear it in the meantime. Do not do this if the pan is already filling up, because it may be blocked.
Do not reach into a cistern while the toilet is in use, and do not bend or force plastic parts inside. They break easily and parts may be specific to the toilet.
Possible causes
These are common causes, not a diagnosis. The actual fault is confirmed on site.
Broken link or cable
Lever toilets use a link or arm. Many push-button toilets use a cable or rod. If it snaps or comes off, pressing does nothing.
Siphon diaphragm worn
In older lever-flush cisterns, a worn diaphragm can mean several pumps of the lever are needed before it flushes.
Fill valve or supply problem
A blocked or failed fill valve, a closed isolating valve or low water pressure can leave the cistern empty or slow to fill.
Low water level or partial blockage
If the cistern does not fill high enough, or the outlet is partly blocked, the flush can be weak even though everything moves.
How WHP would assess it
- Check whether the fault is in the supply, the fill valve or the flush mechanism.
- Identify the cistern type and get matching parts.
- Check for a partial blockage if the flush works but does not clear.
- Test several full and part flushes after the repair.
We explain any call-out or diagnostic charge before booking, and agree the repair and its cost with you before carrying it out.
What affects the price
Every repair is different, so we do not publish fixed prices for this work. These are the things that make the most difference:
- Type of mechanism and whether parts are brand specific
- Concealed cisterns behind panels or wall-hung frames, which take longer to reach
- Whether more than one part has failed
- Whether a partial blockage also needs clearing
Before you call
Useful to send us
- A photo inside the cistern and of the flush button or lever
- Any brand name on the pan, cistern or button plate
- Whether the cistern is filling, and how long it takes
- Whether there is another toilet you can use meanwhile
Get professional help when
- It is the only toilet in the property
- The cistern will not fill even with the isolating valve open
- The cistern is concealed behind a panel
- The pan is filling up or draining slowly. Treat it as a blockage.
Common questions
Why do I have to press the button several times?
Usually because a cable, rod or seal in the flush mechanism has worn or slipped out of adjustment, or the water level is set too low.
Is it the toilet or a blockage?
If the water releases from the cistern but the pan fills up and drains slowly, suspect a blockage. If the cistern does not release water at all, it is the mechanism.
Sources
Safety and responsibility details checked against these sources on 12 October 2026. Water supplier guidance can change. Check your own supplier’s current advice.