(1) No sewer or part thereof may be laid or may pass, as the case may be, within or under or through a building unless the local authority decides otherwise, having regard to considerations of health and maintenance or other matters relevant to the particular case.

(2) Every sewer or part thereof, where it is under a building, shall be –

a) without change of direction or gradient and without means of access thereto except as provided for in section 73; and

b) laid on a bed of concrete at least 100 millimetres thick, having a composition of not more than six parts of coarse aggregate to three parts of fine aggregate to one part of Portland cement; and

c) if the local authority has approved the use of glazed earthenware, encased in similar concrete having a minimum thickness at all points of 100 millimetres, measured from the external surface of the pipe.

(3) Where a sewer or part thereof is laid in an exposed position within a building, it shall be constructed of cast-iron pipes, and shall be adequately supported at intervals not exceeding 2 metres along its course.

(4) No part of the mass pf a wall or foundation shall bear upon a sewer which passes under or through it.