Leaking overflow pipe - please help

[Downnotdown]

I've got water dripping from the overflow pipe from my bathroom and looking for help please. I'm not very good with DIY but have managed to check the toilet cistern and it doesn't appear to be coming from the overflow pipe in there. I have noticed that it does stop occasionally but I can't work out why.

Not sure what else I should be checking before I contact someone who knows what they're doing a plumber. For info, I don't have central heating, only electric radiators, and the water is heated in an immersion tank as and when required. I'm planning to get the bathroom updated in the next few months but am worried about the leak in the meantime.

How many water tanks are in your loft?

Is this dripping pipe behind the WC cistern? Or is it at about gutter level?

Does it drip in the morning and at night when no water has been used for several hours? Or is it when the central heating first comes on?

Please take the lid off your cistern and photograph the internals, including the water level mark on the back.

Oh, I see you have no CH

Is the hot tap water surprisingly hot?

What colour is your hot water cylinder?

Thanks @PigletJohn, for some reason I wasn't notified that you had replied.

The immersion tank is in a cupboard in the bathroom. I've not noticed the water being any hotter than normal. I usually only put it on for an hour or so in the morning.

The overflow pipe does appear to be around where the toilet is located.

I've not worked out any particular pattern about when the dripping stops though.

Please take the lid off your cistern and photograph the internals, including the water level mark on the back.

@PigletJohn, thank you, I will do that later when I am back home.

@PigletJohn, here is a photo of the cistern (finally, apologies for delay). I can't see a tide-mark and I've watched it flush a few times and I haven't seen water go above the overflow pipe inside the cistern. Thank you.

the cistern you show does not have an overflow pipe (any excess drains into the WC pan) so it's not that.

Consider the water tank that supplies your hot-water cylinder.

What colour is the cylinder?

Leave the heater on for two hours. Does the dripping start? Is the tapwater surprisingly hot?

It would be better if you went and had a look at this tank. It will either be in the loft, or directly on top of the cylinder.

Do you have mixer taps? Do they have a joystick, or individual knobs or capstans for hot and for cold?

Do you have a shower mixer?

Put your thumb over the bathroom tap. Turn the hot on. Can you stop the flow? Now turn of the hot and try the cold. Can your thumb stop the flow?

Thank you @PigletJohn. Here is a photo of the water tank. As you can see it's quite old. I switch it on for about an hour each morning to give me water for dishes etc. For info the tank is in a cupboard in the bathroom, there is no tank in the loft.

The shower is electric which (I think) heats the water up as it flows through. I've not noticed the water being any hotter than usual and the dripping does stop sometimes but I just can't work out any pattern to it. Many thanks

that looks like a cold water tank. Is there a cylinder beneath it?

Could this "overflow" actually be a condensate drain from the boiler? More photos of everything - overflow pipe, boiler, cylinder etc needed, I think!

I don't think OP has a boiler

"For info, I don't have central heating, only electric radiators, and the water is heated in an immersion tank as and when required."

So there are two other probable causes, either the immersion heater in the cylinder, or the ballcock in the cold tank.

Haven't seen the cylinder yet and don't know what happens if the immersion is turned on for two hours.

it might be an old packaged plumbing system, which could have one or both of those faults..

HaHa. Very, very good and funny, PigletJohn

Can I just say how much I - and I am sure many, many other Mumsnetters - have valued your advice. Commonsense plus expert experience; just wonderful. Thank you.

@PigletJohn, @CasperGutman, @PigletInABlanketJohn (love the name lol)

I've managed to get a plumber to take a quick look at it and he says the problem is the ballcock in the water tank but unfortunately he can't fix it till next year. I'm on a water meter so dread to see the next bill.

Thanks to you all and Merry Christmas