Where's my waste/soil pipe?!!

[spike66k]

Hi
I'm looking to build an extension on the back of my house(with a bathroom) but can't find any manhole covers or plans to shower where my existing sewage goes! Last owners put a patio over where I guess any manhole might have been.
Rather than dig holes in the patio, is there an alternative idea out there, to help me map out where the waste goes, so I can drop a soil pipe down the new extension to join it??
Next door has a 2' x 3' manhole cover around 10' from the rear of my house. Sorry if it's a dumb question, but any help would be fab!
Thanks
Spike

 

[PrenticeBoyofDerry]

Your local water utilities/authority, will need contacting. They will also be interested in the connection being made.

 

[Hugh Jaleak]

Try the Water Company, as sewerage provider they may have a plan of the approximate location of the run. If it's a shared sewer it's their responsibility anyway. Metal detector may help find any covers, (assuming they're not newer plastic types!), or CCTV and locating tools can be used to trace a blind run if you're really stuck! As said you will need Building Control approval to make a new connection into an existing drain, but this should be tied in with the whole job as you are building an extension.

 

[spike66k]

Thanks very much, I'll try Thames water and see if they can shed a little light on its location.
I appreciate greatly your replies.

 

[ree]

With your neighbour's permission, open their manhole and observe for flushing discharges from your property.
If nothing is seen then it eliminates a shared sewer.