top of page

Plumbing FAQ: Water continuously trickling into my toilet pan?

One of the questions we’re often asked by our customers at our plumbing and heating counter is why water is continuously trickling into their toilet pan and how this problem can be fixed.

This is usually one of two problems:

A: The flush valve base sealing washer needs to be replaced.

If you have a push button operated valve installed (in some cases a lever flush valve that isn’t in the style of a traditional lever flush syphon) you’ll likely have a small rubber washer at the bottom of the valve which is attached to a cental “plunger” which lifts when the toilet is flushed and subsequently closes to stop more water from entering the pan and to allow the toilet cistern to refill.

This problem can usually be solved by replacing the base seal, this ensures that you should not experience any problems in the near future, it may also be a good idea to purchase a couple of these so that you have a spare washer on hand whenever you may need it. Sometimes the washer is in a reasonable condition but limescale has built up on the surface of the washer resulting in an uneven surface. This can then cause the washer to not sit flush against the surface of the flush valve’s “cradle” at the bottom of the cistern. This can often be solved by giving the base sealing washer a rinse in warm water, a mildy abrasive sponge may also help in removing the particularly stubborn areas of limescale, however it is advised not to be too rough with the washer, as splits in the rubber may occur.

Unfortunately some flush valves do not have user-serviceable base sealing washers or the washers are not made available separately from the manufacturer. In such a case, the flush valve itself would need to be replaced. This is usually as simple as twisting out the old valve from the “cradle” at the bottom of the cistern, disconnecting the button (or lever in some cases) and simply inserting the new valve into the cistern and re-attaching the button to it.

B: There may be a fault with the inlet valve / inlet valve diaphragm washer.

If your inlet valve (the assembly usually to the left or right of the flush valve in the center of your cistern) is constantly filling the cistern, water will overflow either down an overflow tube (wouldn’t trickle into the toilet pan) or down into what is known as an internal overflow which is commonly found in the center of the flush valve and will then trickle down continuously into the pan.

In some cases your inlet valve may have developed a fault, in such a case the inlet valve may need to be replaced. Often, a small rubber washer inside of the inlet valve called an inlet diaphragm washer may need to be replaced, these are usually available separately. You can easily find out if it’s your inlet valve by lifting up the float on the side of the valve. If the valve continues to run when the float is fully lifted up, the inlet valve has developed a fault or it’s inlet diaphragm washer may need to be replaced.

We provide the parts mentioned above for some of the most common brands including Derwent Macdee, Thomas Dudley, Fluidmaster, Torbeck, Armitage Shanks, Ideal Standard, Geberit, Grohe, Roca, Impulse, Siamp, Wirquin and many more.

Can’t identify which part you need? Take a few pictures or bring the part into to our shop where our experienced staff are here to help.


bottom of page