An order may authorise undertakers on whom it confers any power or imposes any duty to execute any works required for the discharge of their functions thereunder and may authorise them for that purpose—
(a)to exercise in any specified locality the powers contained in sections twenty-eight to thirty-four of the [10 & 11 Vict c. 117.] Waterworks Clauses Act, 1847; and
(b)to enter upon any specified land after giving to the owner and occupier thereof not less than seven days notice in writing and to occupy and use the land to such extent and in such manner as may be requisite for the execution of the works.