Updated 4.04pm: TWEED Council said that after consultations with the NSW Department of Health they've been given the all-clear to resume normal operations at the Uki Water Treatment Plant
Investigations revealed that the insecticide contamination was likely to have been contained to the site and adjacent drains.
Council advise that if any insectiside reached the river it was of a 'very insignificant quantity' and because of high river flows it posed no risk to human health.
Uki Residents are advised they can resume normal water usage.
Initial report, 2.56pm: Precautions were taken to prevent possible contamination of Uki's water supply with termite poison yesterday afternoon.
Residents were advised to conserve water after the town's supply was shut down and water had to be trucked in.
Tweed Shire Council's manager of water and wastewater Anthony Burnham said a contractor was injecting termite poison into the ground at the Uki sports field on Monday afternoon.
A council inspector noticed the insecticide was running off into a grass stormwater drain that flowed into the Tweed River, upstream of the Uki Water Treatment Plant.
"The council inspector noticed it and stopped everything. He got onto his superior who told the right guys at council," he said.
Mr Burnham said the council had done their very best to stop anyone ingesting the chemical under difficult circumstances and had not heard of anyone who had been harmed by, the insecticide.
The town's water supply was drained completely through hydrants to minimise harm to residents.
"The inspector arrived at 3.00pm and we had the water turned off at ten to five," he said.
"It was very haphazard. We did some doorknocking and let our after hours phone staff know in case anyone tried to contact them wondering why the water was off. The first that residents may have known was when they had no water."
Mr Burnham added that because off the low amount of rain yesterday, it was thought that there was either little to no contamination of the water supply.
"The drain was 400 metres from the river on grassed over land. Heavy intense rain at the time of the spill would have been our worst enemy," he said. But the chemical binds to the grass quite well."
"Three and a half million litres flow past the site every day. The plant is very small and the chance of it picking up the worst of the contamination is low."
Mr Burnham said that the Uki reservoir was half full after water was trucked into the town and was hoping water supply would be back to normal by late this afternoon or tomorrow.
"We're co-ordinating with New South Wales health. If they're unsure of whether there is contamination we may need to truck water in tonight," he said.
"The EPA (Environmental Protection Agency) will obviously be involved with our environmental health people."
Many insecticides are widely known to be carcinogenic, mutagenic and toxic to human reproduction, and they can also cause other health issues.