A leak in a mains pipe has drained Morrinsville's treated water supply to a "critically low" level, the Matamata-Piako Distict Council says.
The Waikato town, which has a population of about 6000, is dealing with an "emergency water shortage" caused by a burst in a pipe going into the reservoir, the authority said in a Facebook post.
"Residents are asked to use water for essential use only," the post said.
The council urged people to only use water for essential health or hygiene needs and to avoid flushing toilets, showering or using washing machines if possible.
Council spokeswoman Eion Scott told Stuff the leak was found this afternoon and crews were digging to find the leak and fix it.