Help - mystery toilet leak!

[xplosiv]

Hi All

I have a recently discovered a mystery leak in my toilet and I'm hoping someone here might have an idea what the matter could be.

Water is dripping from a butterfly screw underneath and the cistern tank (which presumably connects the tank to the toilet). The leak is not constant (for example, I dried the floor before bed and it was still dry this morning) but when it does start up it is very slow and can last for hours. To give you an idea, it might leak half a tea-cup of water throughout the course of 12 hours. You'd think if there was a crack in the tank the leak would be constant?

I've had a look inside the cistern tank - admittedly without taking out any parts since I know very little about plumbing / toilets - and could see nothing obvious.

There doesn't appear to be (though I could be mistaken) any particular event - such as a flush pull - that triggers the leaking.

A family member of mine - who, like me, is no plumber - is convinced the problem is somehow related to either the floaty-ball thing in the tank perhaps occasionally sticking (though I have never noticed this happen before) or a leak in the part which fills up the cistern with water, leading to water coming over the top of the tank. I initially thought this could be the cause as there, surprisingly, isn't an overflow valve in the cistern. However, when we tested out the theory by filling up the cistern tank as far we could we couldn't get the water to overflow because the excess water went down into the toilet "basin".

So, the only thing I can tell you is water is somehow slowly escaping from the cistern and leaking onto the floor from the screw socket.

Providing it's something other than a crack in the system, do you think the problem should be fix-able without replacing the cistern tank and/or whole toilet?

Any ideas / help from plumbers out there would be much appreciated!

Thanks!

 

[seco services]

If it don't leak all the time and only starts to leak when flushed
i would suspect the do-nut washer between the cistern/pan.
It's a foam washer or some are rubber that seals between the cistern/pan.

You'd need to take a look some sit direct on to the bottom of the flush valve some have a metal plate fitted first.

 

[ChrisOxford]

Good advice as always from SS, if the leak definitely gets worse just after you flush (and nice pics too).

But if it does NOT leak more when it's just been flushed, it's more likely to be the seals around the two nuts/bolts which secure the cistern (top bit) to the pan (bottom bit).

Not a big job, but not one to DIY unless you're reasonably competant at plumbing, as there are bits which you'll need to remove then replace which are sometimes quite tricky to get watertight again (even plumbers struggle somtimes). Your plumber would fit a new doughnut washer (that SecoServices mentioned) too.

[As you suspect, your relative isn't right in this particular case. Your loo has an "internal overflow" which is why the excess water ran into the pan when you deliberately overfilled the cistern. This has been standard practice in this country for a few years now. In the past, an overflow (also known as a warning pipe) would have been run through the wall to the outside, and would have been seen to drip if there was a fault with the ball valve which caused the cistern to overfill.]

Good luck.

 

[xplosiv]

Many thanks for the replies - very helpful.

I'm not planning on dealing with this myself, i'm going to instead get my uncle over. He fitted his own bathroom and so i hope he'll be up to the task!

By the way, I noticed the screws fixing the cistern to both the wall and toilet below are very rusty and I doubt they can be used again once the cistern has been removed. Are these screws pretty much standard and available to buy at somewhere like B&Q?

Again, much appreciated.

 

[ChrisOxford]

Do the job when your plumber's merchant is open, so that you can take along the old bolts/nuts/sealing washers/doughnut washer and get exact replacements.

B&Q is probably the best of the big DIY sheds for plumbing bits, but won't necessarily have exactly what you need.

Some plumber's silicone sealant (e.g. Fernox LSX or the cheap equaivalent from Screwfix) is useful in addition to the rubber sealing washers around the bolts.

Is your uncle the family member referred to above?

 

[xplosiv]

No, the family member I referred to was my Mum!

Thanks!

 

[ChrisOxford]

You'd think if there was a crack in the tank the leak would be constant?

If the cistern isn't firmly fixed to the wall, try rocking is slightly. You might notice the leak worsening as the seals between the cistern and pan are flexed.

Your uncle will no doubt be careful when he's re-assembling everything not to overtighten the two bolts and to do them up evenly, as it's not impossible to crack something if you're heavy handed here!