Separate vent pipe to drains located by boundary

[Modernista]

The renovation property I'm buying is a 60s bungalow and it has a slightly strange separate vent pipe near to the boundary (c.20m from house). It doesn't seem to be anywhere close to any other drain runs. It may be like this because the unusual house design means there are no downpipes or gutters generally and perhaps it was sited here to avoid smells etc - but why so far away from the main drain runs? Or could it belong to something else perhaps like a neighbour's drain (although nothing logical in terms of proximity for that either). Anyone seen anything like this? The site is wooded so it will be blocked with leaves etc. I''m going to get a cctv drain survey of the main runs accessed via the manholes I've shown but short of feeding the drain cam down the vent pipe I guess t'll remain a bit of a mystery. There are no rodding eyes apparent anywhere.

[ProDave]

It is probably the vent pipe for the drains.

 

When I was building this house I tried to okay it with building control to not have a vent pipe through the roof and instead just use air admittance valves.  They would have agreed to it IF I had an upstream vent pipe outside the house.  For me it was too late as I had concreted the space beside the house for parking so it was too late to do that, but an upstream vent like that could do away with the need for a vent pipe through the roof.

 

We have such a vent on the side ot the static caravan, but BC would not accept that as being "permanent"

[Modernista]

39 minutes ago, ProDave said:

It is probably the vent pipe for the drains.

 

When I was building this house I tried to okay it with building control to not have a vent pipe through the roof and instead just use air admittance valves.  They would have agreed to it IF I had an upstream vent pipe outside the house.  For me it was too late as I had concreted the space beside the house for parking so it was too late to do that, but an upstream vent like that could do away with the need for a vent pipe through the roof.

 

We have such a vent on the side ot the static caravan, but BC would not accept that as being "permanent"

Thanks Dave - yes that would make sense given that this house doesn't lend itself to such things as an attached vent pipe - the eaves projection is is about 500mm for a start. It just seemed so disconnected - but perhaps just concerns re smell etc