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A leaking toilet cistern will not only keep you awake at night but it will be flushing away litres of wasted water! This could be costing you more money than you think!

A No Probs Plumbing Electrical Emergency Plumber can easily fix leaking toilet issues for you! We are your Perth Emergency Plumber!

Does your toilet continuously leak into the toilet bowl?

There are two common reasons why your toilet cistern may be leaking into your toilet bowl, these reasons are, a worn out inlet valve or a perished outlet washer.

Worn out Inlet Valve

The inlet valve which controls how much water enters the toilet cistern can over time become worn out, this can cause excess water to enter the toilet cistern, which then overflows into the overflow pipe. The water that overflows into the overflow pipe can then be seen dribbling down the inside of the toilet bowl.

How to check your inlet valve?

To inspect your toilet cistern for a worn out inlet valve, take a look inside your toilet cistern. The float on your inlet valve should rise with the water level, which then tells the inlet valve when to shut off. If the float valve doesn’t work properly, the inlet valve will continue to allow water into the toilet cistern, which will then spill over the overflow pipe and into the toilet bowl. The best way to check for the correct operation of your inlet valve is to flush the toilet and watch as the water rises, ensuring that the inlet valve stops allowing water into the toilet cistern once the cistern is full. With some inlet valves, there may be a screw adjustment which can be used to adjust the water level. After making adjustments, if the inlet valve continues to allow water to flow into the overflow pipe, you may need a replacement inlet valve.

Perished outlet washer

An outlet washer creates the seal between your toilet cistern and the toilet bowl, over time these washers can perish or form bubbles inside the rubber causing them to leak. When your cistern outlet washer is faulty, water will leak from your toilet cistern, flowing into the toilet bowl.

How to check for a faulty / perished outlet washer?

To inspect your toilet for a faulty or perished outlet washer, which may be causing a leaky toilet you should follow the following steps.

  1. Turn off the isolation tap which is supplying water to the toilet cistern.
  2. Ensure no water is entering the overflow pipe inside the toilet cistern.
  3. Take a small piece of toilet paper and place it on the edge of the rear section of the toilet bowl.
  4. Observe for signs of water running down the bowl and wetting the toilet paper.
  5. Inspect the piece of toilet paper for any sign of water.

Alternatively, you could turn the isolation tap off and mark the inside of the toilet cistern, after a period of time, if the water level has gone down then this would suggest that the outlet washer is allowing water out of the toilet cistern, causing a leaky toilet.

Both of these issues will cause your toilet cistern inlet valve to operate intermittently, which may even keep you awake at night.


At No Probs Plumbing and Electrical Perth, we always recommend replacing both the inlet valve and outlet washer at the same time, as when one of these parts is worn out, it is common for the other part to be near the end of its working life too.

Drain Dillon


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