Recent rainfall has significantly reduced the available storage capacity at the Kyneton Water Reclamation Plant and is impacting works to improve water treatment processes.
The Bureau of Meteorology has forecast wetter conditions in the upcoming months as a result of the current La Nina weather event.
"The recent rainfall has caused a sharp increase in lagoon levels at the water reclamation plant," Coliban Water managing director Damian Wells said.
"Last week 55 millimetres of rain fell in the region over two days, resulting in inflows to the plant which increased lagoon volume from 85 to 98 per cent.
"Typical inflows to the plant average 2 megalitres per day and last week we experienced a day in which plant inflows exceeded 11 megalitres.
"We are currently releasing tertiary treated Class B recycled water to the Campaspe River, which is compliant with our Environmental Protection Authority (EPA) Victoria licence conditions for water quality and river flow dilution. Tertiary treated water is from the domestic system at our plant.
"With more wet weather forecast and until Phase 2 is completed early in the new year, we will need to release additional Class B recycled water to the Campaspe River."
Mr Wells said a range of operational measures have been put in place to store and treat as much water onsite as possible.
"From Monday around eight truckloads a day will transport approximately 200 kilolitres of treated water per day to help create lagoon storage space at the plant," he said.
"We are continuing to keep downstream landowners and the EPA informed on plant operations. Weekly updates will be provided via our website until lagoon levels decrease and the irrigation season commences."
Mr Wells said phase one works were finished in March with current works part of phase two.
"(This) includes the construction of an additional 200-megalitres storage lagoon at the plant," he said.
"We had planned this would be completed by December this year, however wet weather is impacting the works onsite and we now anticipate works to be completed early in new year.
"This delay, together with the delayed start to the irrigation season, has put pressure on our plant operations and lagoon levels."