Hamilton City Council is keeping a close eye on the Waikato River following a water main and wastewater pipe break in Lake Taupō on Tuesday afternoon.
The water main broke at 2pm on Tuesday afternoon causing a large washout on the lakefront.
About an hour later the footpath collapsed and took out a wastewater pipe, resulting in about 800,000 litres of wastewater entering the lake.
Hamilton City Council compliance manager for City Water Trent Fowles said increase monitoring is taking place on the river from which Hamilton draws all its water.
"Hamilton City Council does not anticipate any disruption to the supply," Mr Fowles said.