Sewage smell in bedroom but not in bathroom/kitchen!

[stevenlewis]

Hi and thanks in advance for any pointers on this one!

For a few days now we've had a really strong sewage smell in our spare bedroom. We've checked and there are no damp patches, evidence of mice/pests or anything in the room to cause the smell. There are no holes in the walls and no vents. The house is fairly modern - built in 1988.

The room is next to the bathroom and the sewer pipe is in the wall between the two rooms, but there's no smell in the bathroom, and all traps seem fine. The kitchen is below the room and again, no smell there. There are no other sinks, toilets etc in the house. The sewer pipe goes through the wall down through the kitchen and then underground.

I've been in the loft, and no smells there and checked the pipe out of the roof (only visually after a shower) and there was a small amount of steam suggesting the vent is fine.

We've had no blockages and there's nothing visually wrong externally or internally.

Does anyone have any thoughts on what this possibly could be? I plan to call a local plumber but I'm not even sure what they will do to test!

Many thanks for any thoughts!

 

[cr0ft]

A seal in the soil pipe letting sewage gas through but not water. It's not uncommon to find this at the top of pan connectors on WCs as they get old. Too high for water to leak out but enough of a gap to let sewage smells come into the room. A soil stack can be tested to verify this using a manometer and test plugs.

 

[stevenlewis]

A seal in the soil pipe letting sewage gas through but not water. It's not uncommon to find this at the top of pan connectors on WCs as they get old. Too high for water to leak out but enough of a gap to let sewage smells come into the room. A soil stack can be tested to verify this using a manometer and test plugs.

Many thanks for the helpful reply. I'll be calling a local plumber on Monday.