Cistern Leaking

We Can Be There Today!^*

Licensed toilet repair plumbers across Adelaide, Perth & Brisbane

G★★★★★
4.6 · 2,000+ Google reviews

A leaking cistern wastes water every minute and only gets worse. Our licensed plumbers find exactly where it is leaking and fix it fast, usually by replacing a worn valve, washer or seal.

We carry common cistern parts to finish in one visit across Brisbane, Perth and Adelaide, with upfront fixed pricing.

Why choose Same Day Trades for a leaking cistern?

We are local, licensed and insured plumbers who do this work every day, so we get it right the first time, with no mess and no surprises on the invoice.

Fully licensed and insured plumbers
Upfront fixed pricing before we start
Same-day service where we can, with 24/7 phones
Workmanship guaranteed and the job left clean
Servicing Brisbane, Perth and Adelaide

Whatever the job, you get honest advice and a tidy, professional result.

Why is my cistern leaking?

A leaking toilet cistern wastes water and can be an ongoing nuisance, but it is usually a straightforward, affordable repair. The cistern holds the working parts of your toilet, the inlet (fill) valve, the flush (outlet) valve, and the button or lever, and most cistern leaks come down to one of these parts wearing out, or a worn seal or connection. A cistern can leak internally into the bowl (a running toilet), externally onto the floor, or between the cistern and the pan. Where the water is coming from tells us what is wrong, and in most cases replacing a worn valve or seal fixes it. We repair leaking cisterns across Brisbane, Perth and Adelaide.

Where is the cistern leaking from?

Finding the source is the first step. Common cistern leaks are:

Internally, from the cistern into the bowl (a constantly running or refilling toilet), often invisible
From the inlet (water) connection where the supply enters the cistern
Between the cistern and the pan, from worn seals or bolts
From the cistern body itself, if it is cracked
From the button or valve assembly

A leak from a valve, seal or connection is repairable; a crack in the cistern means it needs replacing. We trace the leak to its exact source and advise accordingly.

The constantly running cistern

The most common cistern problem is one that constantly runs or keeps refilling by itself, which is an internal leak, water escaping from the cistern into the bowl, and it can waste thousands of litres and add noticeably to your water bill. The usual cause is a worn flush valve or flapper that is not sealing, letting water trickle past continuously, or a faulty inlet valve that will not shut off, or the water level set too high so it runs into the overflow. Because the water goes straight into the bowl, this leak makes little noise and leaves no puddle, so it is easy to miss. We identify and replace the faulty valve to stop the running and the waste.

Inlet (fill) valve faults

The inlet valve, also called the fill valve or float valve, controls the water flowing into the cistern after a flush and shuts it off when the cistern is full. When it wears or fails, it can cause several problems: water continuously running into the cistern and out the overflow, a cistern that fills very slowly, a cistern that will not fill at all, or a hissing or whistling noise as it fills. A faulty inlet valve is a common, repairable cause of a leaking or running cistern. We replace it with the correct part, restoring proper filling and shut-off, so the cistern fills quickly, stops at the right level, and no longer runs or overflows.

Flush (outlet) valve faults

The flush valve, or outlet valve, sits at the bottom of the cistern and releases the water into the bowl when you flush, then seals again so the cistern can refill. When the flush valve or its seal wears, it stops sealing properly, letting water leak continuously from the cistern into the bowl, which is the classic running-toilet leak. A worn flush valve can also cause a weak flush, as water escapes before the flush, or a flush that will not stop. It is a common, repairable part. We replace the flush valve and its seal, stopping the internal leak and restoring a strong, clean flush that stops properly afterwards.

Leaks at the cistern connections

A cistern can leak externally from its connections, usually the water inlet connection where the supply pipe enters, or between the cistern and the pan. A leak at the inlet connection is typically a worn washer or a loose fitting, an easy fix. A leak between the cistern and the pan, from worn seals or bolts, can drip down behind the toilet and be mistaken for a base leak, so identifying the true source matters. These connection leaks are inexpensive and quick to repair once located. We check the seals, washers, bolts and connections, replace the worn parts, and confirm the leak is resolved, so water is no longer escaping onto your floor or behind the toilet.

A cracked cistern

Occasionally a cistern leaks because the ceramic itself is cracked, which, unlike a worn valve or seal, cannot be reliably repaired and means the cistern needs replacing. Cracks develop from age, impact, over-tightening of bolts, or stress, and can be fine and hard to spot. If you have a persistent external leak with no obvious loose fitting or worn seal, a hairline crack in the cistern may be the cause. We can confirm whether a crack is behind the leak and replace the cistern, or the whole toilet if appropriate, so you are not left with a leak that no amount of new washers will fix. It is also a chance to upgrade to a modern dual-flush unit.

How much water does a leaking cistern waste?

A leaking or running cistern can waste a surprising amount of water, often thousands of litres over weeks and months, all adding to your water bill for no benefit. An internal leak from the cistern into the bowl is especially sneaky, because it makes little noise and leaves no visible puddle, yet it can run continuously day and night. A simple test is to put a few drops of food colouring in the cistern and wait without flushing; if the colour appears in the bowl, you have an internal leak. Fixing a leaking cistern usually pays for itself through the water it saves, as well as stopping the annoyance of a constantly running toilet.

Repairing vs replacing cistern parts

Most cistern leaks are fixed by replacing the worn internal part, the inlet valve, flush valve, or a seal or washer, which is far cheaper than a new cistern or toilet and restores normal operation. Sometimes it is worth replacing the inlet and flush valves together if both are old, to avoid a return visit. Replacement of the whole cistern or toilet is only needed when the ceramic is cracked, the unit is very old with parts hard to source, or you want to upgrade to a water-efficient model. We give you an honest assessment and fit the right parts, so a leaking cistern is usually a quick, affordable repair rather than a full replacement.

Dual-flush cistern problems

Modern dual-flush cisterns, with separate half and full flush buttons, are great for saving water but have their own common faults. The buttons or the valve mechanism can stick or wear, causing the toilet to run, flush weakly, or not stop after flushing. The flush valve seal in dual-flush systems is a frequent culprit for a running toilet. These are repairable, and replacing the worn valve or button assembly restores proper dual-flush operation. We carry common dual-flush parts and know the mechanisms across the major brands, so we can repair a faulty dual-flush cistern and get both the half and full flush working correctly again, stopping any leak or running in the process.

How much does cistern repair cost?

Repairing a leaking cistern is usually an affordable job, especially common fixes like replacing an inlet or flush valve, renewing a seal or washer, or sorting a dual-flush button. The cost depends on the fault and the parts needed. A repair is almost always far cheaper than a new cistern or toilet, unless the ceramic is cracked, in which case replacement is the better value. We carry common parts so many repairs are done in a single visit, and we give you an upfront fixed price before we start, so you know the cost, with the water bill saving from stopping the leak often offsetting the repair.

Same-day plumbing service

A leaking or constantly running cistern wastes water every day it is left, so there is no need to wait. We offer fast service and same-day appointments where we can across Brisbane, Perth and Adelaide, and we carry common inlet valves, flush valves and seals, so most cistern repairs are done in a single visit. Our phones are answered around the clock. Whether your cistern is running, overflowing, or leaking from a connection, we will find the cause and fix it quickly and affordably, with an upfront price, so you stop wasting water and money on a problem that is quick to solve.

Preventing cistern problems

A few simple habits help your cistern last longer between repairs. Avoid using in-cistern cleaning blocks that sit in the water, as these can degrade the rubber seals and valves over time and cause leaks. Deal with a running or leaking cistern promptly, before a worn valve wastes more water. If your water pressure is very high, it can stress the inlet valve and connections, so having the pressure checked and limited if needed protects the cistern. And when a valve is replaced, fitting quality parts helps it last. These small steps reduce how often your cistern develops faults and extend the life of its internal components.

Licensed, guaranteed plumbers

Fixing a leaking cistern is best done by a licensed plumber who will find the real source, fit the right part, and leave it working and leak-free, rather than a temporary fix that runs again soon after. Our team is fully licensed and insured, we repair running, overflowing and leaking cisterns, replace worn valves and seals, and service dual-flush mechanisms, and we back our work. You get upfront fixed pricing, same-day service where we can, tidy work and an end to the leak and wasted water. For a plumber near you for a leaking cistern, we cover Brisbane, Perth and Adelaide.

Leaking cistern FAQs

Why does my cistern keep running?

Usually a worn flush valve or fill valve inside the cistern. It wastes water and is a quick, affordable repair.

Why is water leaking between my cistern and toilet?

That points to a worn doughnut seal or connector between the cistern and pan. We replace the seal to stop the leak.

How much does it cost to fix a leaking cistern?

A valve or seal replacement is affordable. A cracked cistern needs replacing, which costs more. We quote upfront.

Can a cracked cistern be repaired?

No, a cracked cistern cannot be reliably sealed and should be replaced. We can supply and fit a new one.

How much water does a running cistern waste?

A constantly running cistern can waste thousands of litres a year, noticeably increasing your water bill.

Can I fix a leaking cistern myself?

Some confident DIYers can swap a valve, but a plumber will get it right quickly and check for other issues like a failing seal.

Do you carry cistern parts?

Yes. We carry common flush valves, fill valves, washers and seals, so most leaks are fixed in one visit.

Do you offer same-day service?

Yes. We can usually fix a leaking cistern the same day across Brisbane, Perth and Adelaide.

Leaking Drain Under Basin Or Sink

We can all agree that a leaking drain under basin or sink is one of the most common household plumbing issues. Kitchen and bathroom sinks,

Pipe Repairs

Are blocked drains or damaged pipes disrupting your plumbing network? Get in touch with us at Same Day Trades for effective solutions at the earliest.

Replace Taps

If you notice sudden leaks or rust-riddled water, it may be time to replace taps immediately. Fortunately, you have come to the right place. Contact

Collapsed Drain

Pipes in the plumbing system of some homes may be blocked frequently due to various reasons. Sometimes roots may enter the pipes through the cracks

Leaking Toilet

If you find constant puddles of water or condensation in a portion of the toilet, it means you’re dealing with a leaking toilet! There are

Install Taps

If your tap is faulty or looks outdated, you will want to replace it. And you’ve come to the right place for it! To install

Snake Down Drains

There can be multiple causes of a clogged drain, and it can prevent sinks and toilets from working. And snake down drains serve as excellent

Downpipe Replacements

Downpipes carry rainwater from gutters and let it reach the soil to prevent it from splashing or dripping down the roof. This way, the extra

Same Day Trades4.6

Based on 2041+ reviews

See all reviews

review us on

Mat Williamson

We really appreciate the professional, courteous and friendly service. Thankyou

Richard Sk

Matt did amazing job and excellent service.

breanne shaw

Jack our plumber was great, really took the time to make sure everything was perfect. Came and connected our new fridge and then fixed our pressure issue at our new house. Would highly recommend

Smart Clean Corporation

Excellent and friendly

Anna . Nunn

Jordan is an amazing person he did an excellent job for my hot water service. The taps were leaking and he fixed the leaking taps. His service was very good.

Ellie D

Very pleased with the service I received by Dom, Diego and Jordan. Communication was excellent. The job was done extremely fast (same day as the quote was done), and the ceiling fans that were being installed look fantastic. I was especially impressed with Dom, who when faced with a obstacle during the install, he came up with a solution which allowed the job to go ahead. Highly recommend.