Fosse Septique Pt2

I have been talking to a Artisan that is looking at installing the fosse septique in our French Property. Things have become a little clearer in that I now know that the filter bed for a 4000litre tans needs to be 6m x 5m  ie 30msqm in plan (3m x 10m or 7.5m x 4m will just not do!). The filter bed needs to drain to water course or alternatively a 25m length of land drainage pipework. The filter bed must be covered in topsoil and cannot be trafficked over. Apparently the quality of inspection and interpretation of the rules governing installation of a fosse varies from region to region. Fortunately in the Charente the inspectors are strict. These installations are cheap so it has to be right and perform correctly so that's fine by me.

I hope to get some photographs of the actual  installation work so will post again soon