The informal ceremony will take place at 2.00pm onsite at the new pump station, adjacent to the oxidation ponds.
The new pump station allows wastewater from Ashhurst to be pumped to the City's main wastewater treatment plant in Totara Road.
"The new pipeline is one of several re-directions of wastewater from outlying towns to the main City treatment plant," Rob Green waste services manager said.
The Council is working closely with Horizons Regional Council and other Manawatū River Leaders' Accord signatories, to reduce the number of discharge sources and enhance the quality of the river.
The overall project has an $8million budget and once completed the city will have only one point of discharge into the river.
Linton and Aokautere have already been redirected and construction of the Longburn connection has started and should be completed by the end of July.
"We are working hard to improve the quality of the river system and Ashhurst residents will soon see the 'do not swim' signs" removed," Rob said.
The new pump station and pipeline have been designed to cope with the increase in Ashhurst residents over the next 50 years.