Yesterday afternoon, Clutha District Council issued a drinking water advisory to the 2153 residents on the North Bruce, South Richardson and Moa Flat water schemes, which include Waihola, Heriot and Kaka Point.
The advisory said levels of aluminium exceeding new drinking water standards of 1mg/litre had been discovered during recent testing.
The levels had since dropped below threshold, and residents could continue to use their drinking water with no risk to health.
The council was also providing water tankers in the affected townships.
Clutha Mayor Bryan Cadogan apologised for any anxiety caused.
“I know some people will be feeling anxious about this and that’s understandable.
"We’ve been told that with the acute levels of aluminium exposure for the period of time we’re talking about, there is negligible risk to people’s health.
"Residents in these areas can keep drinking their water if they want to."
He said a single high-level sample was also found in Kaitangata, although subsequent testing was within standards.
At Waitahuna, an exceedance occurred when a filter was bypassed for several days.
Once the filter was restored, aluminium levels returned to accepted levels.
The first samples showing exceedances were received by the council on February 1 and water regulator Taumata Arowai was informed at that time, he said.
The council engaged Taumata Arowai and Te Whatu Ora Health New Zealand to ensure correct technical, public health and toxicology advice.
It was told no health effects would be expected at these levels of aluminium exposure, even if water was consumed over a period of weeks to months.
This included effects for people with kidney disease, infants and children.
The cause of the elevated levels was yet to be determined, Mr Cadogan said.
"Recording aluminium levels came in with the new drinking water standards in November, so this is the first time we’ve assessed this.
"We ... will be doing everything within our power to remedy the situation, as quickly as possible."
Concerned Clutha residents can find further information and testing results at www.cluthadc.govt.nz/water-advisory.
