A toilet that keeps running — or one that randomly refills itself between flushes — is one of the most common and most overlooked plumbing problems in Melbourne homes. It seems minor, but a running toilet wastes up to 200 litres of water per day, which adds up to thousands of litres per month on your water bill.
Why Is My Toilet Running Constantly?
A running toilet is almost always caused by water leaking from the cistern (the tank on top or behind the toilet) into the bowl continuously. The three most common causes are:
1. Worn Flapper or Outlet Valve
The flapper is the rubber seal at the bottom of the cistern that closes after a flush. When it wears out, it doesn’t seal properly and water slowly leaks into the bowl. You’ll see it as a constantly trickling bowl.
2. Faulty Inlet Valve
The inlet valve controls water flowing into the cistern. If it fails, it either lets water in continuously (causing overflow into the bowl via the overflow tube) or doesn’t let enough water in for a proper flush.
3. Float Set Too High
The float tells the inlet valve when to stop filling. If the float is adjusted too high, the cistern fills above the overflow tube level and water continuously drains into the bowl.
How to Confirm Your Toilet Is Running
A slow leak isn’t always audible. The dye test is a reliable way to check: drop a few drops of food colouring into the cistern (not the bowl). Wait 15 minutes without flushing. If colour appears in the bowl, water is leaking through the outlet valve.
Can I Fix It Myself?
Adjusting the float height is a simple DIY fix — it’s just a matter of bending the arm down slightly or adjusting a screw depending on your cistern type. However, replacing inlet valves and flappers involves working with the water supply and cistern internals, and getting the wrong part or incorrect installation can cause other problems. Most Melbourne homeowners prefer to have a licensed plumber repair it properly for a guaranteed fix.
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How Much Does It Cost to Fix a Running Toilet in Melbourne?
A running toilet repair in Melbourne typically costs $120–$280 depending on which component has failed. An inlet valve replacement or flapper replacement is a straightforward job that most licensed plumbers can complete in under an hour.