The eventual plan was to add more storage ponds, which would allow council to better manage the rate of treated water being discharged, Ms Davis said.
"We are restricted on how much we can discharge on to land because we can't have any run off."
Council is preparing a resource consent application for a long term move to continue to irrigate land at Daleton Farm, which was bought by council in 2012 at a cost of $2.4 million.
The wastewater upgrade project aims to cut the amount of wastewater and nutrients discharged into the Mangaterere Stream during summer, when flows are naturally lower.
Council began discharging treated wastewater on to 19ha of Daleton Farm, adjacent to the wastewater treatment plant, in late December 2014.
The disinfected, recycled water is irrigated at a rate of between 2-8mm per day, depending on conditions, over about 120 days.
Between December and April last year about 150 million litres of treated wastewater were irrigated on to the land, which is leased to a farmer.
A 2.4ha area at the south-eastern corner of the farm is being converted to a wetland.