A report on Wai Comply Ltd's joint independent review into the city's revised water safety plan is due to be finished in January.
The council will use the report to further revise its plan and then submit it to the Drinking Water Assessor for approval.
Said city council head of three waters and waste Helen Beaumont: “We’re making excellent progress with the review, which has involved a number of assessments, workshops and inspections of our water supply network and operational procedures.
“Our aim has been to protect public health and demonstrate that we can supply safe drinking water without the need for permanent chlorine treatment.
“We’re looking forward to receiving the final report next month so we can take the next step.”
Enough well heads across the city have now been upgraded to supply the city with water from secure wells. However, the city council has had to keep a low level of chlorine in some areas until its water safety plan is approved.
Currently about a third of the city is chlorine free, with the remainder on the lowest chlorine dose since treatment began last year.
The council has so far upgraded 111 of its 148 well heads and installed an ultra-violet treatment facility to disinfect water from six wells at one of the city's largest pump stations, Main Pumps.
A new deeper well will also be drilled in Papanui over summer at the Grassmere pump station, which supplies about three per cent of the city’s drinking water.
