Dreadful smell of poo from next door

[nauseated]

The problem started in Oct 2018 and has been going on ever since. It started with what smelled like rancid meat or fat being heated. It was so bad in the back bedroom of the house where I usually sleep I had to open the window and keep it open open all night even though it was cold. Since then the smell is overwhelmingly of poo. It starts anytime during the day or night, but tends to be worse at night. There tends to be no smell when next door are out during the day. Sometimes the smell at night is so bad it wakes me up, and several times I've had to go and sleep in another bedroom. At its worse it smells like you are in a room with a toilet which has just been used but not flushed. The smell is just as bad in the back living room of my house which is immediately below the back bedroom. I don't share any drains with next door and they have a separate manhole to the one for my house. I've lived in the same house for over 30 years and have never had even cooking smells from next door, but I have been told that the back wall of both houses (semi-detached) is a cavity wall, and that the smell from next door may be being vented into the cavity. Next door had a sewer flood about 3 years ago, after their manhole was blocked with tarmac from nearby roadworks. They clearly had drainage problems after this and were continually sluicing out the outside area of the house near where the soil pipe is situated. Then in 2017 a drainage company spent several days at the property carrying out some sort of repairs. I suspect that this didn't remedy the problem and that some other 'solution' has been introduced, but what it is exactly I don't know. It appears to be something that is switched on and off. I'm retired and now spend a lot more time at home so having to contend with the nauseating smell from next door is awful. Next door has been un-occupied between Christmas and New Year and there has been no smell, but it's back today (New Year's Day) with a vengeance. The other complicating factor here is that I am not on good terms with next door and can't ask what is going on. I've been told I can talk to environmental health about the problem and ask them to investigate, but I know that if I do this will only cause more friction with next door. I'd first like to try to establish what drainage 'solution' next door are using, how the smell is getting into my property, and if there are any steps I can take to stop it.

 

[king of pipes]

It is obviously a drain problem either blocked or broken if it your neighbours then I would contact your environmental health dept if you are on bad terms accusations will only make things worse , kop

 

[Ric2013]

It is obviously a drain problem either blocked or broken if it your neighbours then I would contact your environmental health dept if you are on bad terms accusations will only make things worse , kop

Then you aren't accusing anyone.

To be fair, it could be a problem with your drains that has become highlighted by action next door. Unless you have independent septic tanks, at some point the independent drains will run together to a public sewer at which point the stench from one could run up the other. So some level of interdependence of services is almost inevitable.

To give an example, my own house runs to a manhole that then runs to the next manhole at which point it becomes shared by the neighbour. When the neighbour converted to an air admittance valve instead of open vent, I started to notice drain smells in my bathroom. Turned out there was a tiny air leak within the soil stack that previously had been subject to less pressure.

Back to your problem, quite possible that the issue is a public sewer issue, or yours, or the neighbour's, or another neighbour's and at which point environmental health may have an answer or suggestions as to how you could pinpoint the problem. Although if the fabric of your building is spot on, then any external defect shouldn't really be affecting you, so I'm confused.