Pipes in the foundations of extension

[puzzled82]

Apologies if this is posted in the wrong section.

We are currently in the process of building a single storey extension. While the foundations were being dug the sewer pipe and a second pipe which seems to be carrying rainwater was discovered. One pipe is clay and the other seems to be cast iron. The clay pipe was broken by the builder and we have been told will be replaced by a plastic pipe. I don't think the building control officer will approve it being broken either. However yesterday we noticed clear (seemed like clean) water leaking underneath the pipes and dripping into the foundation trench. Would there be a clean water pipe running with the sewer pipe.
What would be the best way to repair the pipe. Would epoxy resin fix it. I personally don't think it is a good idea as the pipes will be sitting beneath the foundations and the pipe can leak again in the future.

I may be being over cautious and it may just be the rain water pipe that has been broken but there was no rain yesterday?

 

[noseall]

when digging foundations and pipes runs are unearthed, it is normal (in wet weather) to see water tracking along the trenches in which these were originally laid.

in fact, when digging through clay, groundwater will follow these tracks and be seen to continually pour from the disturbed trench. this is because the water is following the least path of resistance. disturbing an old land drain can fill a foundation trench with water run-off overnight!

there is nothing wrong with your builder repairing drains in plastic provided it is done correctly. the old 'butted together' terracotta land drains however are not compatible with 110mm modern drainage, as they are smaller. it may be necessary to use something like 65mm rainwater pipe and some cobbled together fittings, i.e. fernco jubilee clip style.