Section 28(iii) in The Punjab Capital (Development and Regulation) Building Rules, 1952
(iii)The size of bathroom shall be not less than 1.85 sq. mts. with a minimum width of 1.2 metres. The minimum size of water-close shall be 1.1 sq. mts. with a width of 0.9 metre. If it is a combined bathroom and water- closet, the minimum area shall be 2.8 sq. mts. with a minimum side of 1.2 mts.
