Yorkshire Water has begun the search for contractors for two civils frameworks worth £1.04bn as part of the AMP7 spending period starting in 2020.
The larger of the two deals is the complex civils framework, which is valued at £750m over five years.
Potential works covered by the agreement include demolition, treatment structures, above and below-ground pipework, service reservoirs and bridges.
Yorkshire Water is expecting to appoint six contractors to the complex civils framework.
The second deal covers minor civils and is valued at £290m, also over five years. Yorkshire Water has not put a figure on the number of contractors it will select for this framework.
Minor works could include road repair, building repair and refurbishment, demolition and installing pipework.
Yorkshire Water has the option to extend both frameworks for a further three years when the initial five-year agreements end.
Requests to participate in the bidding must be submitted by 10 September, with invitations to tender set to be sent out on 17 September.
Water companies in England and Wales are currently preparing for the AMP7 five-year spending period.
For AMP6, which covered 2015 to 2020, Yorkshire Water had six contracting partners including Balfour Beatty Utility Solutions, Morgan Sindall Grontmij and Morrison Utility Services.