Auckland’s water supplier could need to spend up to $180m urgently to find alternative sources of water if insufficient rains fall through winter, worsening the city’s drought.

The spending is signalled in Auckland Council’s emergency Covid-19 recovery budget and would pay to extend treatment for Waikato River water, for ‘modular’ treatment plants at Pukekohe and near an unused source at Papakura plus possible new measures such as desalination of seawater.

Watercare, the council company that runs the water and wastewater systems, has already committed to about $70m of the spending to try to get ahead of a potentially severe drought through next summer. The $180m total is the top end of its contingency in case rains don’t start to re-fill storage lakes in the Hunua and Waitakere ranges.