I have been renovating a Victorian Terrace house. I had it re-plumbed a few years ago. When doing so a durgo vent was fitted in the loft.

While digging in the front garden recently I found a capped old concrete/clay pipe that leads back to the main soil drain.

My question, was this once a soil vent pipe? And if it was should I reinstate it? We had to lower the garden in front of the house, so now it sticks out the ground. I either want to cut the pipe to lower it and recap it or fit a soil vent pipe if it’s required. Other houses in the area have what appears to be a vent in their front gardens.

Cheers,

Ideal would be to trace it back to whatever manhole or junction where it connects to the main drain and block it off there. So there isn't an unseen "dead leg" left lurking under your front garden that will leak in future or confuse the next owner who happens to dig a trench through it!

You could hose through it and see if it is actually blocked off somewhere already, might be a leftover from a previous sewer system that got replaced sometime?


Suction in drains is created when water falls at high speed down a tall vertical soil pipe and drags air away down with it. Buried main drains should not have long vertical falls, so shouldn't need additional vents, beyond those provided by the various households connected to them. When your terrace was originally built there might not have been indoor/upstairs bathrooms - when those were added, complete with vented soil pipes, they would have taken over the function of providing ventilation.