Toilet question

[Jethro]

Hi all,

I have a bungalow with 2 toilets main and cloakroom, both fitted by me in the last 12 months.

A couple of times I have thought I have imagined the water level in the bowl of the cloadroom toilet was lower than it should be, but one flush, things seemed OK. Definitley no leaks under or around it.

On saturday, I went to use the main loo, and the water level was lower ... so much so that the back of the U bend was uncovered. Pondering on it, I flushed, and watched. The level went back to normal, and then about 5 seconds later, it fell, as if sucked down. I flushed again, and it stayed OK, and has been since.

So I have some questions please :

1) Is this normal ? If so, what causes it. Remembering my basic physics the pressure in the sewer must have dropped, so why ? 2) Could it have anything to do with out soil stack ? Birds nest/ blackage ? 3) ... depending on 1/2, is it anything to worry about ?

Thanks in advance

[Tony Williams]

Was there a high wind outside, creating transient vacuums on the top of the stack?

[Bob Eager]

I find that this can heppen if there is a high wind... (not from the loo user!)

[Jethro]

Funny you should say that, there was .... it all makes sense now ! So maybe the answer is my soil stack is not blocked, quite the reverse !