Plumbers are worried about the amount of lead in some people’s drinking water.
Industry organisation Master Plumbers discovered a tap for sale online which leached more than 70 per cent of the recommended level.
"You should be able to go to your kitchen sink and have a drink of water and know that it's trustworthy [and] safe," says Master Plumbers chief executive Greg Wallace.
The group now wants the Government to bring in tougher standards after buying five random taps off Trade Me and discovering one brand, FTL, was leaching high levels of lead.
While four were okay, Mr Wallace said the Government needs to do more testing.
"I think one is too many, but we've known from evidence from Australia up to 8 per cent of communities have been affected by this issue," he said.
The Ministry of Business Innovation and Employment says four similar taps were sold through Trade Me and it’s investigating how they got into the country.
"Trade Me has removed the listing from their website and is monitoring the trader to ensure similar listings from this trader do not appear," a statement issues by the ministry says.
"Given this is a contained issue, it does not indicate a systemic problem requiring a review of plumbing products at this stage."
But the concern is standards are only voluntary – meaning the quality of taps and pipes aren’t verified. Building and Construction Minister Jenny Salesa said that’s not good enough.
"One of the things that I'm looking at is whether we look at incorporating a watermark system, which would look at all of plumbing products to ensure that they are of a certain quality," she said.
But changes will only happen once the Government finishes a complete review of all building products – and that started eight months ago.
Master Plumbers says that will take too long, and the matter needs to be dealt with urgently.