Drain query for new extension

[twowheeler]

Good Morning

We are about to have work start on a small extension for a utility room. THis will involve connecting a new waste pipe to the existing inspection chamber at the rear of the house. This currently takes just the waste from the kitchen and goes under the garage to meet another chamber at the front that takes the waste from the bathroom. From here it goes to the road. I have had a look at the chambers of the neighbours on both sides to check where they go. They do not join onto mine anywhere but both have an inlet or outlet that points away from their properties in the opposite direction to that you would expect. They are an an angle which intersects with our boundary on each side which might suggest there is a drain running across our property to which we are not connected and. We have no other manholes in our back garden.

Now to my concern! We will have to have a soakaway built to deal with rainwater runoff and I don’t want the builders to hit an unmarked drain with all the consequences that would involve. Needless to say the water people say they have no plans for the local drains as the houses were built in the 60s and merely warn me of the dire financial outcome should a drain be damaged.

Any ideas of my best course of action would be most appreciated.

Thanks

 

[r896neo]

You can use a cat scanner with a signal generated pushed down the suspected pipe to trace its position.

Or with a drain rod down the neighbours manholes you should be able to fell where they join the possible shared pipe. Mark this point on the surface roughly and then run a stringline bwteen them. This should give you a fairly good guide where it is and then you can carefully hand dig where your new trench will intersect this line to hopefully find the offending pipe.

 

[freddiemercurystwin]

Or just ensure you pass on your info to your (good) builders and allow them to do their job.