Residents may face water restrictions as soon as next week as the river supplying the city's water is at risk of running low.
The Ōreti River flow has been in the low range for around three months. Photo: Wikipedia
The Invercargill City Council said the Ōreti River flow has been in the low range since December.
It would be the first time water restrictions have been put in place since 2018.
There is a condition under the council's permit to draw water that requires water conservation measures depending on the river's flow.
The first trigger is when the flow falls to or below four cubic metres per second.
Early last month, flow dropped to approximately six cubic metres per second.
The council's infrastructure group manager, Erin Moogan, said when the river flow dropped to the first trigger point, unattended hosing or sprinkler use would be prohibited.
That could happen as soon as early next week, she said.
"The Ōreti has been struggling for quite some time and it will take quite a bit of rain to recharge the river feeding systems.
"NIWA is predicting another dry autumn, which, after a dry summer, means we have to be prepared for the Ōreti levels to drop significantly."
The second trigger is set at 3.2 cubic metres per second.
If that is reached, all domestic outside use of water including washing cars and watering gardens would be prohibited, she said.
Water restrictions were last applied in January, 2018, which also marked the first time the second trigger point was applied.
"The second trigger can be quite soon after the first so people should be prepared."
She said it was important for the council to follow the measures set by Environment Southland to protect the Ōreti river.