Hong Kong Regulations

BUILDING (STANDARDS OF SANITARY FITMENTS, PLUMBING, DRAINAGE WORKS AND LATRINES) REGULATIONS - REGULATION 48

Falls of drains

Every drain or private sewer shall be laid with a minimum fall from its
highest inlet to its connexion with a public sewer or other outlet in
accordance with Table XII below.

TABLE XII

Diameter of pipe Fall 100 mm 150 mm 225 mm 300 mm 1 in 40
1 in 70
1 in 100
1 in 150 (L.N. 294 of 1976)