The capacity was 14m, so it had still had some ways to go.
It was estimated that the impounded supply would be able to reach 12m by Christmas, but that was also heavily dependent on rainfall and the associated river flows.
Chapman said the council was taking water from the river in accordance with what was allowable under consent through Horizons Regional Council and doing it in a "pragmatic way that negates environmental impact".
Residents were also being asked to fill any private swimming pools gradually.