The Ontario Building Code | Minimum Size of Building Drains and Sewers

7.4.9.4. Minimum Size of building Drains and Sewers

(1) Every sanitary building drain and every sanitary building sewer shall be at least 4 in. in size.

(2) Every storm building drain and every storm building sewer shall be at least 4 in. in size.

7.4.10. Hydraulic Loads