How to Fix a leaky Toilet by replacing the Float Valve


Fix leaky Toilet

The toilet float valve allows water to enter the tank of your toilet, when the water level rises so will the hollow float / ball, at a certain point the toilet float will reach its highest level causing it to shut off the valve to stop the water supply to the toilet cistern. When a float valve or ballcock wears out it will not close properly anymore and water the water level in your tank will keep on rising and eventually seep down into the toilet bowl.

All toilet cisterns will start leaking if the washers on the float valve get worn out or, on with some older toilet tanks, the valve seals will wear out and the hollow ballcock will crack and lose its buoyancy. Often it will be a lot easier just to install a new float valve unit than it is to replace just the worn out valve seals.

How to Fix a Noisy Toilet

A toilet can make a lot of noise when filling the tank, this can be particularly annoying when the toilet is in a bathroom right next to your bedroom. The noises are often simply caused by the flow of water, however in some cases, when the pressure in the water line entering the cistern is too high, the ball / float can start to bounce up and down on the flow of water and send noises though your entire plumbing system.

Noisy toilets can be fixed in two ways:

  • Install a new float valve / ballcock assembly which has a bottom entry. (This will fill the cistern from the bottom rather than from the top.)
  • Install a flexible silencer tube to the outlet pipe from the float valve. (This tube is just short of the length of the cistern, and will fill the tank silently from below.

Replacing your old float valve

To install the brand new universal float valve, you need to attach the float valve, then open the water supply and then check for leaks and adjust the float and water levels. To unscrew the inlet valve and ball float, first you will need to turn off the water to the tank and flush it once to empty it.

If you are going to replace our old toilet float valve, our advice is to replace it with a modern diaphragm valve. These are quite inexpensive and readily available from your local plumbing supply or hardware store.

Installing a diaphragm valve

  • First you need to isolate the tank, when there is no valve turn off the main water supply.
  • Now drain the toilet's tank by flushing the toilet.
  • For water storage tanks, lower the water level by at least 6 inches first.
  • Then disconnect the inlet pipe from the valve.
  • Use 2 spanners to disconnect the float valve assembly from the tank.
  • Now remove the float from the worn valve and connect it to the new one.
  • The assembly should go through the hole in the side of the tank.
  • Screw the nut onto the threaded shaft.
  • Connect the float valve assembly using 2 spanners, and reconnect the inlet pipe.
  • Turn the water supply  back on and watch closely for leaks as the cistern fills

Replacing a diaphragm valve

  • First you need to isolate the tank, when there is no valve turn off the main water supply.
  • Disconnect the retaining cap from the valve inside the tank at the end of the float arm.
  • When the retaining nut is located at the front of the cistern then you should see the diaphragm behind the cap.
  • When the retaining nut is at the back of the tank then you need to move the cartridge assembly to get to the diaphram
  • Now before  you place the new diaphram make sure to clean all the parts in cold water first.
  • Then reassemble the float valve and turn the the water back on.

Adjusting the water level in the tank

The water level in a Toilet's water tank is controlled using the float on the float valve assembly. By lowering the float when the valve is closed, you will let less water into the cistern.

The ideal water level is approximately 1 inch below the overflow outlet. You can adjust this in a number of ways depending on the type of float valve you have in your toilet.

  • If the float arm involves a 90° kink at the end, and the float/ball is attached with a thumb screw to the arm, the height of the float can be adjusted by loosening the thumb screw and lowering/raising the float on the arm.
  • Diaphragm valves often contain an adjustment screw where the float arm is attached to the valve assembly. The further the screw is in, the lower the float.
  • If the float/ball is attached directly a solid metal rod, the float can be lowered/raised by bending the arm down or up

Faulty flap valves

If a Toilets tank will not flush, or requires you to flush a few times, then it cold well be that the flush valve needs replacing.

Usually the flap valve is located right at the base of the tank, and it is operated by pressing the handle on the side or the front of your  toilet. When you let go of the handle, the lever will lift the flap valve to allow water in the toilet's tank to flow through the siphon trap into the bowl. As the water level in the tank lowers, so will the plastic flap valve until it seals off the plate, blocking the siphon to stop water flowing out of the tank. When the water level in the tank rises again the flap valve stays in position. If you want to know more about plumbing solutions, you can go and visit

Replacing a broken flap valve

  • First isolate the tank, or when there is no isolating valve turn off thewater supply at the main.
  • Now drain the tank by completely flushing the toilet .
  • Then disconnect the arm inside the tank.
  • Use a wrench to unscrew the large nut securing the flush pipe.
  • Move the flush pipe to one side a little and place a bucket underneath.
  • Unscrew the retaining nut which secures the siphon to cistern.
  • Now lift the siphon assembly from the tank and remove the diaphragm from the metal plate.
  • Replace the worn diaphragm with the new one.
  • Then reassemble the flush mechanism and reattach the flush pipe.
  • Turn the water supply back on and check for any leaks as the tank fills.

External References

Related articles: 

Add new comment

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
By submitting this form, you accept the Mollom privacy policy.