Why Your Toilet Keeps Running
A cistern that keeps running has water escaping somewhere between flushes, and three parts own nearly all the blame. If your toilet keeps running, the noise is the clue to which one.
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This guide works through each fault, the dye test that proves a leaking cistern, and the line Queensland law draws around home owner repairs. We're Ferny Hills plumbers, and running cisterns sit among the most common calls we take. Ferny Hills Same Day Plumbing works across the suburb's 1960s to 2000s housing, every job is done by a licensed plumber, and we attend same-day where we can.
Inlet Valve, Flush Valve Seal and Overflow Explained
A running cistern points to one of three parts. The inlet valve may refuse to shut off, the flush valve seal may pass water into the pan, or the level may sit high enough to spill through the overflow.
The inlet valve refills the cistern after each flush and stops once the float lifts to its chosen mark. Sediment or wear can leave that valve partly open, so the tank fills slowly or never stops filling at all.
The flush valve, or outlet valve, holds the water in reserve between flushes. When the rubber seal perishes, water slips past into the pan, and the cistern refills by itself every few minutes with nobody near the button.
The overflow sends excess water down into the bowl rather than across the floor. Water reaching that outlet means the cistern is filling past its level mark, so the level setting or the inlet valve behind it needs a look.
Each fault leaves a signature:
- A steady hiss that outlasts the refill points to the inlet valve.
- A quiet top-up every few minutes, or water tracking down the back wall of the pan, points to the seal.
- A dripping overflow pipe, often outside, points to a level set past its mark.
The Dye Test for a Leaking Cistern
Run the check by putting a little food colouring into the cistern water, holding off flushing, then reading the bowl. Colour showing up in the bowl means the flush valve is passing water down between flushes, since nothing else moves cistern water there.
A clear bowl means the flush valve is holding, so the level and the inlet valve become your next checks. Flush once you've read the result, because the colouring washes straight out of a ceramic bowl without leaving a stain.
No colouring in the house? Rest a strip of dry toilet paper high on the rear wall of the pan, above the water line. A strip that stays dry means no trickle. A damp strip means water creeps down the pan, and the flush valve seal is your suspect.
Slow, Partial or No Refill After a Flush
A cistern refusing to fill usually comes down to an inlet valve blocked by sediment or worn out, a float riding below its mark, or a stop tap left part closed. Start at the stop tap, since that small isolation valve left part closed can quietly strangle the flow for years. A float riding low also cuts the refill short before the water nears its mark.
Water running without the level climbing tells a different story. The flush valve seal may be draining each refill as fast as it arrives, and no float adjustment will hold back a leak like that.
Where Home Owner Toilet Repairs Stop
Queensland's regulator treats three cistern parts as unregulated work, open to anyone with the right knowledge and skill to swap:
- the drop valve washer
- the float valve washer
- the suction cup rubber
Unregulated work needs no licence, approval or report, though the result still has to satisfy the standard Queensland's plumbing codes set. We give no repair steps here, because the legal line stops at those three parts.
Every other toilet job counts as minor work, which belongs to a QBCC licensee, with no permit and no Form 4. Queensland tenancy law gives the owner or manager the repair duty, and the tenant has to pass on faults as soon as they notice them.
The emergency repair list for rentals covers an unusable toilet, blocked or broken. A cistern that merely runs stays off that list, so the fix is routine, done within a reasonable time after the report reaches the owner.
Who Pays for Water a Cistern Wastes
No, the concealed leak adjustment Unitywater offers leaves toilet cisterns out, along with leaking taps, hot water systems and other appliances. So a running cistern's wasted water lands on the owner's bill.
Property owners hold primary responsibility for leaks and losses on their side of the meter, while Unitywater looks after the mains and the sewer. A quiet cistern can run for weeks before anyone notices, so the dye test earns its place in any Ferny Hills bathroom.
When to Hand the Job to a Plumber
Ring us once the dye test proves the cistern leaks and the three unregulated parts are not the whole story. Ferny Hills housing runs from the 1960s subdivisions through to 2000s builds, with fittings of every age within a short drive of the shops by Ferny Grove station, just across the boundary.
Hand the job over when:
- the bowl shows colour and the cistern needs more than the three unregulated parts
- water still leaves through the overflow after the level has been reset
- scale furs the internals, or the porcelain shows a crack
Anything past those parts belongs to a licensed plumber, and our toilet repairs service covers the rest, from worn seals through to replacement suites.
Running Toilet Questions We Hear
Call (07) 3523 6484Why does my toilet keep running after I flush?
Usually a worn seal on the flush valve. Water seeps past into the bowl, so the inlet valve keeps topping the cistern up in a slow loop. A steady hiss once the refill finishes shifts suspicion to the inlet valve, and spills from the overflow point to the level.
Why is my toilet cistern not filling up?
Three things usually explain it: an inlet valve blocked or worn out, a float riding below its mark, or a stop tap left part closed. When water runs but the level stays flat in a Ferny Hills cistern, the flush valve seal is letting each refill drain away as it arrives.
Will Unitywater cover the cost if my toilet keeps running in Ferny Hills?
No, the concealed leak adjustment from Unitywater excludes toilet cisterns, so the wasted water stays on the owner's bill. Owners carry primary responsibility for leaks on their property. The repair price depends on which part failed, the cistern type and access, and a fixed quote before any work starts settles it.
What is the overflow in a toilet cistern?
A safety outlet that routes surplus cistern water down into the bowl rather than over the floor. When the inlet valve won't close or the float sits too high, the level climbs until water passes out through that pipe.
Ring Us About Any Running CisternWe'll call you back.
Book on (07) 3523 6484 for plumbing anywhere in Ferny Hills. We're available 24/7, there's no extra charge for nights, weekends or public holidays, and every job comes with $0 call-out fees.
To claim your $0 call-out fee, call (07) 3523 6484 today.