Section 21(1)(b) in The Gujarat Water Supply and Sewerage Board Act, 1978
(b)so much of the sub-soil appertaining to the said water mains and sewers as may be necessary for the purpose of enlarging, deepening or otherwise repairing or maintaining, any such water mains and sewers or any pipes and other appliances and fittings connected with such water supply and sewerage services and sewage works and sewage farms; and