Thanks for quick reply! The tank is to be positioned down slope from the house . There is a drop of about 2 m in 50m. The top of the tank would have to be above the natural ground level to get anywhere near 1:200 just wondered if a steep drop would cause solids to be left behind!
I am installing a bio-disc waste system in a new build on a sloping site. Does anyone know if there is a max fall from house soil pipe to inlet on septic tank?