Levels of lead up to six times the safe limit have been detected at a hospital and health clinic in Far North Queensland.
Chief Health Officer Dr John Gerrard said routine testing at the Health Facility in Yarrabah and the newly-built hospital in Atherton returned results above the WHO standard of 0.01 miligrams per litre.
"Several hundred samples have been taken now across the facilities and it's variable," he said.
"Most of them have been below the cut off, the 0.01 cut off, in some areas where the water has been stagnant, so where the taps have not been used, it's been high — six times over the the WHO guideline."
CHHHS Chief Executive Leena Singh said they did not know where the contamination had come from.
"We're unsure of the source of the lead, but we believe it's coming through the copper fittings and other fittings of the infrastructure areas," she said.
She said samples were taken from facilities annually, and they were made aware of elevated lead levels within the past 48 hours.
Dr Gerrard said, there was a low risk to patients.
"The risk really applies to long-term or continuous exposure to significant amounts of water over a prolonged period," he said.
"The issue mainly pertains to staff who may be drinking water over over that period, but even there, the risk we believe is very small."
He said staff at both facilities were being offered bottled water for drinking and blood tests to test metal levels.
"I emphasise, it's not a risk to the general public outside the hospitals, and it's not a risk to patients who only spend a relatively short period of time there," he said.
The new Atherton Hospital will not be opened until the source of contamination has been detected, according to Dr Gerrard.
Earlier this week, water at the Yarrabah Health facility was found to contain elevated levels of copper.
Ms Singh said both elevated metal levels were detected in the same locations.
"That's usually in the stagnated areas so areas that don't get used a lot," she said.
"So the water sits in the pipe for a much longer period of time, and that's what potentially could be causing the issue.
