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How to Fix a Running Toilet With a Button Flush
Push button cisterns fail differently from old lever ones, and the advice written for a lever toilet will send you looking for parts that are not in there. The mechanism is a drop valve operated by a cable or a pair of push rods, and there are really only three things on it that go wrong.
The Short Answer
Take the button out of the lid first, because you cannot get the lid off with it in place on most designs. It usually unscrews anticlockwise as a collar around the button, by hand. With the lid off, look at the drop valve in the middle: a button flush that runs is nearly always the seal on the base of that valve, the valve failing to drop fully back, or a button assembly stuck part depressed. Only the first of those needs a part.
Getting the Lid Off Without Breaking Anything
This stops more people than the repair does, and forcing it is how a ceramic lid gets cracked or a plastic button housing snaps. The button sits in a hole in the lid, and on almost every design the button assembly has to be released before the lid will lift.
The usual arrangement is a threaded collar surrounding the button, on the top face of the lid. It normally unscrews anticlockwise and is usually hand tight. If it will not shift, do not reach for pliers straight away; a cloth for grip and steady pressure gets most of them, and limescale around the thread is the common reason one feels seized.
A few designs instead have the button unscrew as a whole unit, and some concealed cisterns have a frame that the button plate clips into with the plate simply pulling off. If yours is a flush plate on a wall rather than a button on a lid, that is a concealed cistern and the access panel is the route in, not the plate.
Once the collar is off, lift the lid straight up rather than tilting it, because the drop valve mechanism often protrudes through the hole. Put the lid flat somewhere safe. They are heavy and they break.
How a Dual Flush Actually Works
Understanding this makes the fault obvious. A dual flush cistern has a drop valve, sometimes called a flush valve, sitting over the outlet. Pressing the small button lifts the valve a short way and it drops back quickly, giving the short flush. The large button lifts it further, or holds it up longer, giving the full flush.
The valve is lifted either by a cable running from the button assembly, or by two push rods that press directly down onto the top of the valve. The valve itself sits on a seal at its base, and that seal is the same kind of component as the washer under a lever cistern's flush valve.
So the three failure modes follow directly. The seal at the base perishes or picks up grit and water passes into the pan continuously. The valve does not drop fully back, usually because the mechanism is binding or the cable has been left with no slack, so it sits fractionally open. Or the button itself is stuck part depressed and is holding the valve up, which is a mechanism problem rather than a water one.
The Three Faults, and What Each Needs
Work through them in this order, because the first two are free to check and the third is the only one that needs a part.
- Button stuck part down. Press each button and watch it return. If one sits lower than the other or feels gritty, take the button assembly out and rinse it. Limescale in the housing is the usual cause and it is common in a bathroom where the cistern is rarely opened.
- Valve not seating fully. With the lid off, flush and watch the drop valve return. It should fall back positively onto its seat. If it hesitates, lands crooked, or is held by a taut cable, the mechanism needs adjusting rather than replacing. Cable operated types have an adjuster to set slack, and there should be a little.
- Seal passing. If the button and the valve both behave and water is still moving in the pan, it is the seal at the base of the drop valve. Turn off the isolator, empty the cistern, and lift the valve out. On most designs it releases with a quarter turn anticlockwise, like a bayonet fitting. The seal is a rubber ring on the underside.
What to Replace, and What Just Needs a Wipe
Wipe the seal and the seat it lands on before deciding it needs replacing. A meaningful proportion of these are grit rather than wear, and the repair is a cloth and two minutes. Look at the rubber: soft, smooth and even means it is probably fine; hard, cracked or with a visible groove worn into it means it is not.
If it needs a new one, take the old valve with you. Dual flush drop valves are not standardised in the way an old ball valve was, and there are a lot of near identical parts that are not interchangeable. Photograph the valve in place before you remove it too, so you can see how the cable or rods engaged.
Where the valve body itself is cracked or the bayonet lugs are broken, the whole valve is replaced rather than just the seal. That is still a modest part and it is the same removal, but check the height: many replacement valves are adjustable for height and getting that wrong means the cistern either overfills or never fills properly.
Reassemble in reverse, turn the water back on, and let it fill completely before testing. Then run the dye test from the main guide to confirm the pass has actually stopped, because a partial improvement is easy to mistake for a fix on a slow leak.
Concealed Cisterns Are a Different Job
Worth separating out, because the advice above assumes you can get at the cistern. A concealed cistern sits inside a stud wall or a furniture unit with only the flush plate visible, and access is through whatever panel the installer left.
The mechanism is the same in principle and the faults are the same three. The difficulty is entirely about reach. Some frames give you a generous inspection opening behind the plate; others give you an aperture barely large enough for a hand, and on a few the only realistic access is by removing tiling or a panel that was not designed to come off again.
Before starting, take the flush plate off and look at what the opening gives you. If you can see and reach the valve, the job proceeds as above. If you cannot, that is a genuine reason to stop rather than a failure of nerve, because working blind inside a wall cavity is how a small leak becomes a much larger one behind plasterboard.
Why This Fault Is So Common in Glasgow Flats
Push button and dual flush cisterns arrived here in bulk with a particular wave of work: the bathroom refits that went through the city's private rented stock through the 2000s and 2010s. A great many West End and Southside flats had a period or 1980s suite replaced in that period with a close-coupled dual flush unit, and those units are now old enough that their seals are exactly at the age where they fail.
That gives Glasgow a concentration of one specific fault in one specific type of property, and it is why we see the same handful of drop valve designs repeatedly rather than a broad spread. It also means a lot of the affected flats are tenanted, and the person who notices the noise is often not the person who arranges the repair, which is a large part of why these run for so long.
The other consequence of that refit wave is concealed cisterns behind boxing. Where a bathroom was reconfigured to gain space in a narrow tenement room, the cistern frequently went into a boxed-in section or a stud partition, and the quality of the access left behind varies enormously. Some have a proper inspection panel; plenty were tiled straight over with only the flush plate as a way in. Worth establishing which you have on a quiet afternoon rather than at the point the valve fails.
Hard water is not the driver here that it is in the south east, since the west of Scotland supply is soft, so seals in this city fail from age and from grit rather than from scaling up. That is good news for the repair: a wipe and a reseat works more often here than the same advice would further south, and it is worth trying before buying anything.
When to Call Someone Out
Call when the cistern is concealed and the access will not let you reach the valve, when the flush plate or button housing is broken rather than dirty, or when the valve has been replaced and it still passes, which usually means a worn seat rather than a worn seal. Also worth it if the unit is a discontinued design and you cannot source the part, because we can often identify a compatible valve from the frame rather than the badge. Mo or Kyle cover this work, and on a concealed cistern we will tell you honestly what has to come off before anything starts.
Toilet Installation in GlasgowCommon Questions
On most designs a threaded collar around the button unscrews anticlockwise from the top face of the lid, usually hand tight. Use a cloth for grip rather than pliers, since limescale on the thread is the common reason one feels seized. A few designs unscrew as a whole unit instead. The lid will not come off until the button assembly is released.
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Read Next
Full guide
How to Fix a Running Toilet
Water is either passing from the cistern into the pan, which is the flush valve seal, or the cistern is overfilling and spilling into the overflow, which is the fill valve.
Why Does My Toilet Keep Running?
Listen to the pattern rather than the noise.
Why Won't My Toilet Flush?
Lift the cistern lid and flush.
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