Work is expected to be completed by April.
Sallins wastewater network is to receive upgrading which is due to begin next week, Monday 10th January.
Sallins, Clane, Naas, Newbridge and Kill were served by a wastewater network which was no longer fit for purpose, leading to overflows and flooding during storms.
Irish Water says it is investing over €38 million to solve the problem and to provide additional capacity to support the building of houses, schools, attract new industry and allow companies to expand and grow.
According to Irish water a significant amount of work has already been completed in Clane, Naas and Newbridge which included the construction of over 3km of new wastewater network between Clane and Sallins.
Irish Water, working in partnership with Kildare County Council, is progressing the delivery of the Upper Liffey Valley Sewerage Scheme to safeguard the environment and support economic and social development in towns across Kildare.
The next phase of works is scheduled to begin in Sallins on Monday 10 January 2022 and involves the construction of new wastewater network in a number of areas.
Irish water says to minimise the impact to local businesses and residents, the works will be completed in phases and traffic management will be in place.
Irish Water says that Phase 1 will begin on Monday 10 January and is scheduled to be completed by 23 January, with Phase 2 beginning on 24 January and scheduled for completion on 13 February and phase 3 beginning on 14 February 2022 and scheduled for completion on 6 March.
The Irish Water project team says it will continue to update local businesses and the community ahead of these works.
It says diversion routes will be clearly signposted as agreed with Kildare County Council and An Garda Síochána.
Emergency access and restricted local access will be maintained, including access to local businesses.
The works, which will be delivered on behalf of Coffey Construction Limited, are expected to be completed in April 2022.