Lake Rotorua health warning over wastewater spill to stay over weekend

Lake Rotorua users around the Ngongotahā area have been waiting for the health warning to lift. Photo / NZME

A public health warning for Lake Rotorua in the Ngongotahā area will remain over the weekend.

A maintenance hole overflowed and spilt wastewater into Lake Rotorua last week forcing the Rotorua Lakes Council to issue a public health warning for users to stay out of the lake.

The health warning applied only to the spill area in Ngongotahā, within about a 400m radius of the Waiteti Stream mouth.

The spill happened at a property near the corner of Arnold St and Waiteti Rd and the council said the mishap was caused from a computer glitch.

The Bay of Plenty Regional Council is investigating the incident and is yet to decide whether it will prosecute.

A statement from the council tonight said that despite initial tests on Wednesday indicating the lake water quality at all sample points was within safe swimming guidelines, further testing yesterday indicated higher bacteria levels at two points near the mouth of the Waiteti Stream.

Additionally, following the heavy rain yesterday and this morning, as per the standard public health warning, people should avoid swimming in lakes, rivers, streams and estuaries for a period of 48 hours after heavy or prolonged rain due to potential bacteria contamination from water runoff, the statement said.

For these reasons the health warning will remain in place over the weekend.

The spill, described by locals as brown water "spraying like a fountain", happened at 7pm on October 18. It is estimated that up to 20cu m of wastewater may have reached the lake over three hours.

Test results showed bacteria levels had not dropped as expected after the weekend, prompting more testing to be done this week.