A toilet that leaks, runs constantly, or will not flush is not just inconvenient — it wastes water, drives up your bills, and in some cases points to a more serious plumbing problem underneath. Catalyst Home Services provides toilet repair and replacement across London for homeowners, landlords, and businesses, with same-day appointments available and qualified engineers who carry the most common parts on the van. If your toilet needs attention today, book a plumber online or call our 24/7 emergency line on +44 7400 265421.
What This Service Covers
Toilet problems come in several forms — from a slow cistern that never quite fills to a pan that has cracked and is leaking at the base. Some are a quick repair job. Others are better resolved with a replacement, particularly when the unit is old, parts are no longer available, or the fault keeps recurring.
Our toilet repair and replacement service covers every common fault across all toilet types, including close-coupled toilets, back-to-wall units, wall-hung toilets with concealed cisterns, and low-level suites. Below is a breakdown of what each type of work involves.
Toilet Cistern Repair
What It Is
The cistern is the water tank that sits above or behind the toilet pan. It stores water between flushes and releases it when the flush handle or button is pressed. When the cistern develops a fault, the most common symptoms are water running continuously into the pan, the cistern failing to refill after a flush, or water leaking from the cistern body or the connection between cistern and pan.
Who Needs It
Any household where the toilet is making a constant trickling or hissing sound after flushing, or where the cistern takes an unusually long time to refill, has a cistern fault that is worth attending to. On a metered water supply, a running cistern can add a significant amount to your quarterly bill without you realising it.
What’s Included
We inspect the internal mechanism — the fill valve (ballcock or float valve), the flush valve (syphon or flap valve), and the overflow — to identify exactly what has failed. Most cistern repairs involve replacing one of these internal components, which are inexpensive parts that carry the lion’s share of the wear over a toilet’s lifetime. Where the cistern body itself has cracked, we advise on replacement options.
Toilet Pan Repair & Replacement
What It Is
The toilet pan is the ceramic bowl that connects to the waste outlet in the floor or wall. Cracks in the pan, a loose pan that moves when sat on, or a persistent water leak at the base of the pan all require immediate attention. A leaking pan base usually means the wax seal or rubber connector between the pan and the soil pipe has failed and is allowing waste water to escape onto the floor — a hygiene issue as much as a plumbing one.
Who Needs It
Homeowners who notice damp or discolouration on the floor around the base of the toilet, a toilet that rocks or shifts when used, or a visible crack in the ceramic. Landlords in particular should treat a cracked or leaking pan as an urgent repair given the hygiene implications.
What’s Included
We remove the existing pan, inspect the soil pipe connection, replace the seal or connector, and refit the pan securely. Where the pan is cracked or beyond practical repair, we supply and fit a replacement. We match the replacement as closely as possible to your existing bathroom layout and suite style, and all waste connections are tested before the job is signed off.
Running Toilet Repair
What It Is
A running toilet — one where water trickles into the pan continuously, even between flushes — is one of the most common and most ignored toilet problems in UK households. The sound becomes familiar, and because nothing appears to be visibly broken, it tends to stay on the to-do list indefinitely.
Who Needs It
If your toilet makes a constant sound of running water or hissing after the cistern has filled, you have a running toilet. A toilet running continuously can waste between 200 and 400 litres of water per day depending on the severity of the fault. For households on a water meter, that is a straightforward and solvable drain on your bills.
What’s Included
The most common cause is a worn or warped flap valve that is no longer sealing properly against the flush valve seat, allowing water to slowly escape into the pan. We replace the faulty valve, check the fill valve and float arm for secondary issues, and test the full flush cycle to confirm the fault is resolved.
Toilet Flush Repair
What It Is
A toilet that will not flush, flushes weakly, or requires multiple attempts to clear the pan is a flush mechanism fault. Modern toilets use either a syphon mechanism or a drop valve system to release the cistern water. Both wear over time, and both have specific failure modes.
Who Needs It
This fault is particularly frustrating in a single-bathroom household and should not be left unresolved. Beyond the inconvenience, a partial flush can mask early signs of a blocked drain further down the waste pipe — so it is worth confirming whether the issue is the cistern mechanism or the drainage below.
What’s Included
We diagnose whether the fault is in the flush mechanism, the flush valve, the cistern water level, or the waste outlet. For syphon mechanisms, we replace the diaphragm or the full syphon unit as required. For drop valve (push-button) systems, we replace the valve or the actuator plate. All parts are tested through multiple flush cycles before we leave.
Toilet Replacement & New Installation
What It Is
Sometimes the most sensible solution is a new toilet. Older suites can be difficult to source parts for, and toilets that have had repeated repairs may simply have reached the end of their reliable service life. Replacement is also the right choice when remodelling a bathroom, upgrading to a more water-efficient unit, or fitting a wall-hung toilet to free up floor space.
Who Needs It
Homeowners upgrading a bathroom, landlords replacing an ageing unit between tenancies, and developers or building contractors fitting toilets in new or refurbished properties. We work with Bathroom Fitting projects as a standalone toilet installation or as part of a wider bathroom overhaul.
What’s Included
We remove the existing toilet, prepare the floor and waste connection, supply and fit the new unit, make all water supply and waste connections, and test for leaks and flush performance. We work with close-coupled, back-to-wall, and wall-hung toilets including concealed cistern systems. Customers can supply their own toilet or ask us to source one — we can advise on suitable models for your layout.
Why Professional Toilet Repair Matters in the UK
Toilet installations and repairs that involve the soil stack or the mains water supply fall under the Water Supply (Water Fittings) Regulations 1999. Any fitting that connects to the water supply must be installed to a standard that prevents backflow and contamination — this is not simply best practice, it is a legal requirement for UK properties.
DIY repairs to cistern internals are generally low-risk, but work involving the soil pipe, the waste connection, or the water supply requires an understanding of UK Water Regulations and building standards. A poorly fitted soil pipe connection, for example, can allow sewer gases to enter the property — an issue that is both unpleasant and a genuine health hazard.
Catalyst Home Services engineers work to the relevant UK standards on every job. You can review our licences and certifications before booking.
Who We Work With
Homeowners dealing with a fault that is affecting their daily routine — whether that is a running toilet they have been tolerating for months or a sudden leak that needs urgent attention.
Landlords and letting agents who need a fast, documented repair to meet their obligations to tenants. We understand that response time matters in a rental context and can provide the paperwork your records require.
Commercial clients including offices, restaurants, retail premises, and public facilities. High-use commercial toilets fail more frequently than domestic ones and often need parts that are not available off the shelf. Our Commercial Plumbing team handles commercial toilet repairs and replacement programmes across London.
Developers and contractors fitting out new builds or refurbishments and needing a reliable subcontractor for sanitary ware installation as part of a wider New Build Plumbing package.
How a Toilet Repair or Replacement Works
Step 1 — Booking Call us on +44 7400 265421, use the Book a Plumber form online, or reach us via the emergency line if the situation is urgent. Tell us what the toilet is doing (or not doing) so we can bring the right parts.
Step 2 — Assessment on Arrival The engineer inspects the toilet, isolates the water supply, and identifies the root cause of the fault. Where the problem is not immediately visible — for example, a slow internal leak — we carry out a straightforward diagnostic check before committing to a repair approach.
Step 3 — Clear Quote You receive a clear, fixed quote before any work begins. There are no hidden call-out fees and no hourly rates that escalate without your agreement.
Step 4 — Repair or Replacement The agreed work is carried out. For standard repairs, most jobs are completed within the same visit. For replacement installations, the timeline depends on whether a new unit needs to be sourced, but we aim to complete most replacements the same day or the following morning.
Step 5 — Test and Sign-Off All water connections are checked, the cistern and flush are tested through multiple cycles, and the floor area is checked for any residual moisture. We do not leave until the toilet is working properly and the area is clean.
Why Choose Catalyst Home Services
Catalyst Home Services has been providing plumbing and property maintenance services across London for years, building a straightforward reputation: qualified engineers, honest pricing, and work done to a standard that holds. Our Why Choose Us page has the longer version, but in short:
We are available same-day and around the clock for emergencies. We carry common toilet parts on every van so most repairs do not require a second visit. We price the job before starting, not after. And we work to UK Water Regulations standards on every installation and repair. Read what London customers say about their experience on our Reviews & Testimonials page.
If you have a recurring toilet problem or manage multiple properties, our Residential AMC and Commercial AMC packages provide planned maintenance cover that catches these faults before they become urgent.
Related Services
A toilet fault is sometimes connected to a wider plumbing issue. These services are most commonly needed alongside toilet repair and replacement work:
- Blocked Toilet Unblocking — if the toilet will not flush or is draining slowly due to a blockage in the waste pipe
- Blocked Drain Clearance — if the blockage extends beyond the toilet into the main drain
- Leak Detection & Repair — if the source of moisture around the toilet is not immediately clear
- Bathroom Fitting — if the toilet replacement is part of a wider bathroom renovation
- Water Pressure Issues — if low water pressure is affecting how the cistern fills or how the flush performs
- Emergency Plumbing — for active leaks or situations where the toilet cannot be used at all
Book a Toilet Repair or Replacement in London
Whether it is a running cistern you have been ignoring for months or a pan that has just started leaking, it is worth getting it sorted rather than managing around it. Catalyst Home Services offers same-day toilet repair and replacement across London, with no hidden charges and qualified engineers on every job.
Call us now on +44 7400 265421, use our 24/7 emergency line for urgent situations, or book a plumber online and we will confirm your appointment straight away. We cover residential and commercial properties across London — check our full service areas to confirm we cover your postcode.
Why does my toilet keep running after flushing?
A constantly running toilet almost always points to a faulty flap valve or fill valve inside the cistern. The flap valve sits at the base of the cistern and controls the release of water into the pan — when it wears or warps, water leaks past it continuously. A fill valve that is set incorrectly or has a worn float mechanism can also cause the cistern to overfill and drain through the overflow. Both are straightforward repairs.
How do I know if my toilet is leaking at the base?
Look for water pooling around the floor at the base of the pan after flushing, or for persistent damp or discolouration on the floor that does not dry out between uses. This usually indicates a failed seal between the toilet pan and the soil pipe outlet. It is worth treating this as an urgent repair because the water escaping is waste water, not clean water.
Can a running toilet increase my water bill?
Yes, noticeably. A toilet with a faulty flap valve can lose between 200 and 400 litres of water per day into the pan. For a metered household, that represents a significant addition to quarterly bills over time. The repair itself is typically low-cost compared to the ongoing water waste.
What is the difference between repairing and replacing a toilet?
Repair is the right choice when the pan and cistern body are in good condition and the fault is an internal component — a valve, a seal, or a mechanism. Replacement makes more sense when the toilet is old and parts are difficult to source, when the ceramic is cracked, or when the unit has had repeated faults. We will give you an honest assessment of which route makes better sense before any work starts.
How long does toilet repair take?
Most standard toilet repairs — replacing a cistern valve, fixing a running toilet, resealing the base — are completed within an hour. Toilet replacements, including removing the old unit and fitting a new one, typically take two to three hours depending on the toilet type and the condition of the existing waste connection.
Do you repair wall-hung toilets with concealed cisterns?
Yes. Wall-hung toilets with concealed cisterns require access to the cistern frame behind the wall panel — either through the access panel, if one is fitted, or by removing a section of the wall covering. We work on all major concealed cistern systems including Grohe, Geberit, and Roca, and can advise on access requirements before the job begins.
Is toilet installation regulated in the UK?
Connections to the soil stack and the mains water supply must comply with the Water Supply (Water Fittings) Regulations 1999 and Building Regulations Part H. This means the installation must prevent backflow, ensure correct trap depths, and connect properly to the drainage system. Work carried out to the correct standard avoids future problems with insurance claims and property surveys.
Can you fix a toilet the same day?
In most cases, yes. We offer same-day bookings across London, and engineers carry the most frequently needed cistern and flush parts on the van. For less common components or concealed cistern systems that require specific parts, we confirm the timeline with you before leaving and return as soon as parts are available.