Helen Beaumont, who leads the Christchurch City Council's water supply improvement programme, said the water at the main pumps would continue to be treated even after the city's treatment scheme had ended in 2020.
The city has begun looking at alternative treatment options after public backlash in relation to the chlorination of the water supply. Christchurch began chlorinating its water supply after experts found contamination risks at the city's well-heads.
Beaumont presented a report at an August 23 city council meeting, which outlined four alternatives to chlorination. These were ultraviolet light disinfection, remediation (raising all six well heads above ground and creating a seal around the well casing), moving the pumps to a new site and "doing nothing".
The city council decided to test ultraviolet light disinfection in place of chlorination at the main pumps.
The initial instillation of ultraviolet light disinfection is estimated to cost $2.25 million with maintenance and ongoing costs of about $75,000 a year.