Drainage Problem

[DMC]

Last year I got the French equivalent of Dyno Rod in to solve the problem of my sewage/drain system using camera inspection. The bottom line is that I have a 'fosse ancienne' below a layer of concrete on the ground floor of the house. The house has at some time during the intervening 35 years since new been connected to mains drainage. The sewage goes from the upstairs toilet and down through the fosse to a very small and shallow 'pit' just outside the house where the 'grey' water meets the clean looking water from the fosse. Both pipes (100mm for sewage and maybe 40mm for grey water) meet at this point and go across the garden in 100mm PVC pipe via 2 other small covered pits before disappearing off the premises to the mains drain.

I am now at the point where renovations mean that the upstairs WC has to be moved and an extra one also installed on the ground floor. The sewage from both WCs and the grey water will then all meet at the same point in the small shallow pit just outside the house. Without calling in the professionals, I'd appreciate some feedback on how it should be when finished. i.e. is it OK for 2 WCs and grey water all to meet in the small and shallow pit ( I have my doubts). Also, is there any need for the other 2 pits before entering the mains drain - shouldn't it be just an un-interrupted run?

I will probably be asking for a devis for this job rather than do it myself but some opinions on the correct way to do it would certainly help.

TIA,

Doug

[Michael]

I take it you mean the shallow pit is the first manhole for the wc,if so that should take 2 toilets and all your grey water as you call it easy, the other manholes are for rodding and cleaning purposes,if its a long run to the main sewer thay are normally put  every 40m or less. happy plumbing, in your case rodding.