A new house is blocking our sewer but the owners don’t want to know
Property Clinic: your queries answered
Blocked sewer: Request access to carry out further investigations. Photograph: iStock
Q: Originally the house we live in had a very long back garden, which our wastewater pipe ran the length of, and emptied into the main sewer located in the laneway at the rear of the garden.
The previous owner divided the garden and retained half of it for future development. Subsequent to our purchase of the house and downsized garden, building began on the retained section of the garden.
Our objections and concerns for the proposed development were made known to both the council and the owner but building work continued, was completed and sold on.
Shortly after that blockages began to occur and steadily got worse and worse to the point where we now have no access to the main sewer. We are now reduced to hiring a suction tanker to evacuate the waste from our drain when it accumulates.
The council has advised us this is a private matter between ourselves and the new owners despite our warnings and objections.
The new owners do not want to know as they have a separate feed to the sewer and are not affected by this issue.
Video inspection of the drain indicates that the blockage is directly under our neighbour’s house.
Our engineer has advised rerouting our drain to a main sewer in front of our property and out to the main road.
While the council has given planning permission to carry out the work, the cost is prohibitive. The insurance company argues that the blockage is not on a property which they insure.
We would appreciate any insights or advice you might have for this dilemma.
A: Building houses in rear and side gardens has been quite common over recent years and one would expect this trend to continue, particularly in urban areas. I am assuming that you experienced no general issues with the sewer pipe run prior to the new dwelling being constructed in the rear garden.
From the information provided it appears that the real issues occurred after this dwelling was constructed over the sewer pipe in the rear lawn. This I can see is both annoying and of major concern.
It is permitted to construct a property over a private sewer pipe run, however some basic measures need to be adhered to:
1. First it is recommended that an inspection of the sewer pipe be undertaken prior to carrying out any works to establish whether there are any defects in the pipe run.
2. Care should be taken during construction works not to cause damage to the sewer pipes.
3. The structure being placed on the ground above the sewer should not result in potential damage being caused to the sewer. Special foundation details, etc should be incorporated to ensure that the loading of the new structure does not bear directly down and onto the sewer pipe.
It would appear from your notes above, that there was either a problem with the sewer prior to the dwelling being constructed above or that the weight of this new dwelling has caused damage to the sewer.
If it can be proved that the latter caused the damage, then the neighbouring property owner should be consulted. However, this is now more difficult given the current owner of this dwelling purchased it after it was constructed.
Meanwhile, I recommend the following:
1. Consult with your neighbour and explain the issue to them and request access to carry out further investigations.
2. Have a camera survey carried out on the underground pipe channel runs. This will detail the type, condition of the pipe runs and the pipe route.
3. Depending on the level of damage to the pipe run (is there only damage to the pipe side wall or has the sewer pipe settled in the ground), it may be possible for a specialist contractor to repair the pipes, possibly in situ, without any major works being undertaken).
4. Decommission this pipe connection and reroute your sewer pipe disposal out directly into the mains sewer pipe. Consult with the local authority/ Irish Water with regard to considering a reduced fee for accessing the sewer, given the particular predicament you faced.
Given the information provided I think that you should (if this option is feasible) redirect your sewer pipe away from the neighbouring property and directly to the main sewer.
Andrew O’Gorman is a Chartered Building surveyor and member of the Society of Chartered Surveyors Ireland, scsi.ie