Plumbing Question

Cistern leaking

I had to replace the ball valve in the loo but as soon as the cistern starts to fill up, water leaks through the nut at the bottom of the cistern nt matter how tight the nut is. i've even tried using plumbers tape to stop it but it still leaks through. Is there anything else i can try, and how much should i pay if i get a plumber in?

5 Answers

Best Answer

ok assuming that the cistern is plastic, it would suggest that there is a crack in the base of the cistern, this can only be rectified by replacing the cistern with a new one, prices will vary.
if the cistern is a ceramic one then i would suggest a new rubber washer for the base of the syphon and this will need to be put between the sypon and the cistern and not between the cistern and the nut.
hope this helps

Answered 20th May 2012


Member since 2 Sep 2011

Plumbers mait or a water proof silicone (like LSX from Fernox) to fill the gap and seal the joint .

Answered 20th May 2012

CBA Plumbing & Bathrooms

Member since 20 Apr 2012

it sounds to me like the rubber washer (donut) that goes between the system and the pan isn't sealing if you go to any plumbers merchants you will be able to get a new one for a couple of pounds at most, but if it still leaks i suggest getting a plumber in because you may of over tightned your cistern and put a hairline crack in it

Answered 20th May 2012

sunnyside plumbing and heating

Member since 1 Mar 2012


Assuming that the washer was installed when the ball valve was changed, You could try using either plumbers mate or silicone, both of which is not really the best option. If you have installed the washer, make sure its placed on the inside.

Hope this helps

Answered 20th May 2012

ML Plastering & Building

Member since 11 Apr 2009

Hi, get a plumber out quick fix, think you gone wrong in replaceing it, local plumber wont cost lot ,put job on my builder get some quotes readfeed back, best wishes colin.

Answered 20th May 2012

Rigsby Handyman

Member since 14 Aug 2009

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