Why does my toilet keep running after flushing?

Either the fill valve isn't shutting off when the cistern is full, or the flush valve seal is letting water bleed into the pan so the cistern never reaches its shut-off level. Both are standard parts and both are a single-visit repair.

My toilet flushes weakly. Is that a blockage?

Not usually. A weak flush is most often a worn flush valve or a cistern water level set too low. A genuine blockage tends to show as the water rising and then draining slowly, rather than a feeble flush.

Can you repair an old or discontinued toilet?

In most cases yes — the internals are largely standardised even when the suite isn't. Where a part genuinely no longer exists we'll tell you that rather than fit something that doesn't seal properly.

How long does fitting a new toilet take?

In the same position, with sound existing pipework, typically two to three hours including removing the old suite. Moving the position, changing from close-coupled to wall-hung, or fitting a concealed cistern takes longer.

Is a slow leak at the base urgent?

Yes, more than most people expect. Water running under a floor from a pan connector rots boards and reaches ceilings below long before it becomes obvious.

Toilet Repair | Flush, Cistern & Leak Fixes

The three parts that cause almost every toilet fault

Fill valve (the inlet)

Controls water refilling the cistern. When it fails you get constant running, a slow fill, banging pipes, or water out of the overflow.

Flush valve (the outlet)

Releases the water into the pan. A worn seal lets water bleed through constantly; a broken linkage means the handle or button does nothing.

Seals and connectors

The doughnut washer between cistern and pan and the flexible pan connector into the soil pipe. These cause almost every floor-level leak.

The pan itself

Hairline cracks weep slowly and can't be repaired. If the pan or cistern is cracked, replacement is the only honest answer.

What you can safely check yourself

Take the cistern lid off and look: if water is running over the top of the overflow tube, the fill valve has failed.
Put a little food colouring in the cistern. If colour appears in the pan without flushing, the flush valve seal has gone.
Dry around the base and watch. Water only after a flush points at the pan connector; water constantly points at the supply.
Isolate the toilet at the small valve on the supply pipe before touching anything inside the cistern.
Don't keep flushing a blocked toilet — each flush adds another cistern of water to whatever ends up on the floor.

Repair or replace?

Almost every toilet fault is a repair. Fill valves, flush valves, handles, seals and connectors are standard parts and replacing them is cheaper than a new toilet by a wide margin, even on older suites.

Replacement is the right call in three situations: the pan or cistern is cracked, the suite is an obsolete design where parts genuinely no longer exist, or you're changing the bathroom anyway and it makes no sense to fit new parts to something being removed.

Moving a toilet

Moving a toilet is governed by the soil pipe, not the water supply. Waste needs a consistent fall to run, so short moves along the same wall are usually straightforward and moves to the opposite side of a room often mean re-routing the soil connection or fitting a macerator unit.

A macerator makes otherwise impossible positions workable — a cloakroom under stairs, a loft en-suite — but it is a mechanical part with a service life and it should be a considered choice, not a shortcut. We'll tell you honestly which one your layout needs.

What it costs

Real North West ranges rather than headline prices. You get a fixed price for your job before any work starts.

Job	Typical range	Notes
Fill valve or flush valve replacedStandard part, single visit.	£90 – £160	Standard part, single visit.
Handle, lever or push button mechanismIncludes the part on most common suites.	£80 – £130	Includes the part on most common suites.
Pan connector or cistern seal replacedCures most base leaks.	£90 – £180	Cures most base leaks.
Blocked toilet clearedPriced before we start; recurring blockages may need a camera.	From £85	Priced before we start; recurring blockages may need a camera.
New toilet supplied and fittedClose-coupled, existing position, old suite removed.	£280 – £550	Close-coupled, existing position, old suite removed.
Toilet relocatedDepends entirely on soil pipe routing.	Quoted on survey	Depends entirely on soil pipe routing.

Toilet repair — your questions answered

Not sure yet? Ask KJ first

Describe it in your own words, send a photo or a short video, and get a straight answer on what it is and what it should cost — before you book anything.

Tell KJ what's wrong

Free and no obligation — we'll get a qualified local plumber on it.

Start with KJ

KJ Plumbing Expert · Online now

KJ

online

Honest UK plumbing advice — free, and a local plumber when you need one.

Hi, I'm KJ — honest UK plumbing advice, free, and a local plumber when you need one. Tell me what's happening — leak, blockage, boiler, emergency, anything — and I'll help you sort it.

You can send a photo, short video, voice note or share your location — whatever's easiest. Please avoid sending faces, documents, house numbers or payment cards in photos.

For genuine emergencies call 01706 318200, or the National Gas Emergency Service on 0800 111 999.

What we'll ask →

Common plumbing problems — tap one to start

Toilet Repair — Flush, Cistern and Leak Faults Fixed