Riverton residents will have their drinking water sourced from the Aparima River temporarily while investigations continue into the current state of the town's water supply.

The announcement came today at a meeting in the town over recent complaints over discoloured and foul smelling water in the town.

Southland District Council (SDC) mayor Gary Tong said the decision to switch back to a river supply, rather than a bore supply which has provided the town water for the last three years, was made to ensure the council could get to the bottom of the current issue.

He said while extensive tests of the current water supply had shown it did not pose a health risk to residents, he had heard all concerns raised and that it was the council's "personal responsibility" to ensure Riverton had an adequate and clean water supply.

"We are taking this very seriously...water treatment is a complex science and we have experienced staff doing the best we can to determine the most ideal outcome for all residents of this town."

Mr Tong said the council had received 36 formal complaints about the water since the town switched to bore water, but the recent spate of online complaints through social media had brought the situation to his attention further.

Several concerned residents spoke at the meeting about the issue, with concerns raised over giving the water to young children as well as the cost involved over replacing hot water tanks and filters due to corrosion and calcium build-up.

Riverton residents spoke about their concerns over the water supply in the town. PHOTO: Ben Waterworth

SDC water and waste senior engineer Bevan McKenzie said initial tests had shown that iron displaced from pipes that helped deliver water to residents had caused the discolouration to some residents water.

He said when water went through the pipes at a high velocity, it caused iron to come off and continue through the water.

Tests conducted by the council showed most levels of iron at .002mg per litre, which is the lowest which could be read on the measuring instruments, and as high as .07mg per litre which led the council to make the final decision to switch back to river water.

Mr McKenzie said the water supply could be switched over by the end of next week, however it is expected to take three weeks as they wait for a UV filtration unit to arrive from Te Anau which will help ensure all potential bugs and contaminants are filtered out before going to residents.

Mr Tong said there would be no rise in rates for residents to cover the costs for the changeover as the council had budgeted for a UV filtration unit to be used in the bore water supply.

A time frame could not be confirmed as to how long the river would be used as the water supply, with tests on the bore taking as little as a "few months" to "a couple of years".

The council will inform residents when the switch is set to take place, with a flush of the current system needed to switch over which may cause further disclouration and odour until it is fully switched over to the river supply.

Residents were encouraged to continue to inform council of any issues with their water by calling 088 732 732 or online at www.southlanddc.govt.nz.