Boil water notices have been issued for Ranfurly, Omakau and Ophir after recent rainfall and snowmelt made the towns' source water too turbid to treat effectively.
The Central Otago District Council initially advised of a conserve water notice for Ranfurly this afternoon, but in an update this evening said that an earlier improvement in quality "was not sustained, and a boil water notice is now required".
The notice will take effect from 10pm.
In a later update the council added Ophir and Omakau to the list, effective from 11pm.
"The considerable amount of snowmelt entering the waterways is affecting turbidity and therefore water quality, with the treatment plant unable to continue to produce compliant clean water."
The council said people should boil all water used for drinking, food preparation, cooking, and teeth cleaning your teeth until further notice.
"Bring water to a rolling boil and boil for at least a minute, then allow it to cool naturally."
The council said water tankers would be stationed in Ranfurly by the monument on Charlemont St and at the Maniototo Hospital.
Water tankers would also be stationed at the Omakau School in Omakau and at Blacks Hotel in Ophir.
The council would continue to provide updates.
