Minimum Brick wall thickness of septic tank should be?

Ans. is 'b' i.e., 9 inches"Wall built out of brick should not be less than 200 mm thick and should be plastered to a minimum thickness of 12 mm inside and outside with cement moar not weaker than 1:3; where are built out of the stone masonary.A septic tank is usually provided with brick wall in which cement moar thick and the foundation floor is of cement concrete 1:2:4.