Taupō residents have been warned to stay out of the lake and avoid flushing toilets following a major water main break.
Taupō District Council confirmed that 70 percent of Taupō's wastewater headed straight to the lake.
"It is a main pipe that goes under the bridge to Nukuhau and we are getting a number of reports of no water and low pressure," the council wrote on their Facebook page.
The water main broke around 2pm on Tuesday, causing a large washout on the lakefront. The footpath then collapsed and took out a wastewater pipe, says the council.
While the exact quantity of wastewater to enter the lake is unknown, the clean-up is expected to take several weeks.
Another water main broke around before 6pm this afternoon in Marshall Avenue, Richmond Heights. Taupō District Council advised residents to refrain from any unnecessary water usage.
"We expect it will take about an hour to repair," they wrote on Facebook.
A number of detours have been set up around the area, and some Nukuhau residents may be out of water.