Drainage - how far should pipes be from wall foundations?
 

I am planning a "timber on dwarf wall" type conservatory in place of,
and slightly larger than, an ageing flat roof porch.

The WC soil pipe (to septic tank) and the bath/sink waste pipe (to
soakaway) will need to be moved (approx 1m) along the front of the
house to make space for the conservatory.

The new underground WC soil pipe will have to run parallel to the new
cons. wall straight out in front of the house and connect in to the
existing run to the septic tank.

My initial questions :-
- how close is it advisable (and allowable?) to have the drains to the
foundation of the new conservatory wall? (& is this part worth
bothering the Bldg Inspector?)
This will dictate how wide the conservatory can be.

thanks in advance
Andy