Toilet Flush Button Stuck

What's happening?

A push-button cistern has two parts that can bind: the button unit in the lid, and the flush valve or siphon it presses. On a dual-flush cistern the button presses a plunger or pulls a cable, and a spring returns it. If the button stays down, that return is blocked or the link to the valve is too tight or has come apart. If the button pops up but nothing flushes, the link is slack or broken. Because the valve below can be held slightly open, a stuck button can also leave the cistern running. That is a different fault from the one on the toilet keeps running page: here the button is the problem and the valve is fine once it is freed.

What usually causes it?

• Limescale or grime on the button plunger so it no longer slides freely in its housing
• A cable or rod link set too tight, so the valve is held a little open
• A broken or sheared retaining lug that lets the button fall through the lid
• A weak or displaced return spring in a top-press unit
• A button cap rubbing on the edge of the lid cut-out
• A flush valve that has been swapped for one with a different press height

Is it dangerous?

No. The risk is wasted water and a bathroom you cannot flush. If the button is stuck down and water is running into the pan, the cistern is draining continuously and the inlet valve is refilling it, so shut the isolating valve under the cistern with a screwdriver until it is fixed.

Can I fix it myself?

Lift the lid off first. Most lids simply lift; some are held by the button, which you can unscrew by turning the cap, or by pinching two lugs. With the lid off, press the button by hand and watch what moves. If the plunger sticks, wipe it and its housing with a cloth and a little vinegar for limescale, then work it until it springs back. If a cable link is tight, shorten the adjustment by a turn so the valve closes fully. If a lug is broken, replace the button unit, not the whole cistern: check the make on the underside, or photograph it for a toilet spares supplier. Do not use lubricant that leaves residue on the valve seal.

When should you call a plumber?

Call a plumber when the cistern is concealed behind a panel or frame, when the valve itself is stuck open or will not seal after the button is free, when you cannot identify the make to get a matching part, or when the toilet needs to be flushed with a bucket until someone comes.

What will the plumber actually do?

• Identify the cistern make and whether it is a top-press, front-press or cable-operated dual flush
• Free or replace the button unit and check the lid cut-out fits it
• Set the link length so the valve closes fully with the button at rest
• Check the flush valve seal and the inlet valve while the lid is off
• Test a full and a part flush and confirm the cistern stops filling at its marked line

Who fixes this

• Toilet repair and replacement

Questions people ask

Sources & References

1. WaterSafe: why won't my toilet flush properly
2. The Water Supply (Water Fittings) Regulations 1999, Schedule 2