Low Water Level in WC Pan - Smelly Toilet !

13 Apr 2005
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United Kingdom
The water level in my downstairs wc pan is below the normal level - (accounting for the bend). This means that smelly air from the soil pipe / drains is coming up.

When I flush, the level in the pan returns to normal - then goes down to a low level again. And occasionally makes a gurgling sound , even if I haven't flushed it for a while.

It's like there is a vacuum in the drains.

Is this 'back-siphoning' ? Any ideas on what I can do ?

Thanks, Peter
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It sounds as if there is not a proper air vent in the soil pipe the toilet feeds into.

Probably the work of a cowboy builder!

You can possibly rectify it by fitting an air admittance valve!

I know that it all seems low tech but these matters are controlled by building regulations to prevent healty issues.

My advice would be to get a competent professional who has studied the building regulations. A start might be to get the local Building Inspector in to it but that might result in him serving Notices on yuo to get it properly fixed. It all depends on who the cowboy was and how long ago that was!

Tony Glazier
Or it could be blocked down the line.....both scenarios are possible :cry:
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The toilet is in a 15yr old extension. And I do remember the council making a lot of visits to inspect the below ground level work, whilst in progress - as the extension was a downstairs bathroom for a disabled person.

There is a boxed-in air admittance valve in the bathroom. It is positioned a few inches higher than the top of the wc pan. Do they have to be sited "above the flood level of the highest water outlet in the room"? as quoted on another site. The wc cistern, washbasin and shower outlets are all above its current level.

Would it be better to raise the level of the valve or convert this to a soil stack ?

I suspect there may be a blockage up or down 'stream' as the old outside wc is having the same problem - being on the same line. Probably the neighbours pouring old paint and all kinds of stuff down their outside loo again ! Time to go knocking on people's doors ...

Thanks, Peter

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