The nation's chief medical officer has moved to assure people that household drinking water is safe, after a five-month-old health advisory made national headlines over the weekend.

In July, a committee representing federal, state and territory health departments alongside the NZ Ministry of Health and the National Health and Medical Research Council issued a guidance statement related to lead levels in household water supplies.

"Every effort should be made to reduce exposure to lead in the environment, including lead that may be dissolving into drinking water from some plumbing products," the statement from the Environmental Health Standing Committee read.

Lead continues to be used in the manufacture of some home drinking system products in Australia, and the committee advised that it could dissolve into drinking water if it had been sitting in contact with brass plumbing products for long periods or as some water was heated.

However, the statement also said drinking water supplied to homes and other buildings was safe and elevated blood-lead levels "are rarely found to be related to lead exposure from drinking water".

Overall risk low

Among the advice for households wanting to reduce their exposure was the recommendation that they run water taps for 30 seconds before use in the morning to flush out stagnant water.

Several national media outlets ran this advice as a headline over the weekend, and in at least one instance labelled it an urgent warning.

"Households have been officially warned to run taps for 30 seconds before using water for drinking or cooking in the morning amid growing concern about lead poisoning from plumbing," one report read.

But Commonwealth chief medical officer Professor Brendan Murphy said people concerned they were at risk of lead toxicity could rest easy.

"We've got no evidence at all that anyone has become toxic from lead from drinking water," Professor Murphy said.

"We know it's a toxic chemical to humans; it's just in this circumstance, it's such a tiny amount that's in drinking water that people are just saying if you want to be absolutely sure to reduce it, this is sound advice.

"We're not saying our drinking water is unsafe, and people certainly shouldn't be alarmed."

Some precautions are sound

While Professor Murphy said the greatest risk of lead poisoning came from other environmental sources, such as lead-based paint and fuels, parents should heed the guidance's warning about making up baby formula with tap water.

"Babies are much more sensitive to lead, [so] it might be sensible in that circumstance to particularly flush the water if it's been stagnant overnight before you use it to make up the formula."

He also said the amount of lead contained in some brass plumbing products, which was limited to a maximum 4.5 per cent, was being examined by the Australian Building Codes Board.

Recent research from Macquarie University commissioned by the board recommended that low-lead or lead-free plumbing components be used during the installation of drinking water systems to limit the release of lead into drinking water.

Earlier this year the City of Greater Geelong shut off 30 water bubblers and tested many more after they were found to contain elevated lead levels, believed to be related to the infrequent use of the taps.

No need to test home taps

Professor Murphy said the committee's advice was in response to some concerns about elevated drinking water at various times around the country.

But he maintained the risk was low and there was no recommendation for people to get their water tested.

"Lead is of no value to the human body, and as a matter of precaution, particularly in circumstances where you've got old brass plumbing fittings, the advice is that if you want to be sure to reduce any potential lead intake, you can run your tap for 30 seconds," he said.

"We still have no evidence that not doing that will be of any harm to you, but if you want to be absolutely secure and safe, that's something you can do."