Internal Waste Drain Rise from Outside Grate

G'Day Guy's.

Great Forums, i've just joined but have been using the information most of you give with Gusto on my Owner Builder Project. Nothings fallen down yet so it must be working.

I am wondering if it is possible to install a one way valve in the waste drains of a downstairs laundry and Bathroom to get away from the 150mm rise require from the outside drain grate.
This would mean i don't have to drop the external pathway too much (75mm only for termite protection) and save on removing and replacing the fencing posts and fence etc.

Any help would be gratefully recieved.

dunno but I'd like to see an informed answer too.

In NSW you can use a 100mm refluxe valve that only collects waste from the ground floor fixtures.
The only catch is that the new PVC reflux valves are constructed using a 150mm Pvc T square junction that requires a Bolted Trap Screw or clear out, thus raising the trap screw up above your floor height.
Shane The Plumber