Flushing a cup of water from your taps each morning can help remove some of the metals, such as lead, that can accumulate in water overnight says a Water New Zealand spokesperson.

Water New Zealand drinking water quality technical lead, Belinda Cridge, says the discovery of lead contamination in Tokomaru this week is a reminder of the risk of water contamination from plumbing fittings.

“If water is slightly acidic and has been sitting in pipes for several hours, it can start to dissolve metals from household plumbing fittings.

“This means that small amounts of dissolved metal can enter the water supply.

“That’s why we advise that the equivalent of at least one large cup of water is flushed from taps each morning before filling the kettle or drinking a glass of water.”

She says there is a particular risk around older and some imported taps and plumbing fittings, especially ones that have been bought directly from manufacturers or online.

"Some of these products have been known to contain higher levels of lead than is allowable in recent updates to the Building Code.

“Recent changes to the Building Code have reduced the allowable level of lead in plumbing fittings to 0.25 percent, but the new code won’t be in force until May next year.

“In the meantime, we advise anyone purchasing plumbing fittings to check on lead levels or ask their supplier."

She says while the health risk of drinking water with dissolved metals is small, a build up of heavy metals in your body can cause health problems in the longer term.

“It is particularly important to ensure that children do not drink water that has been contaminated with metal and that’s why we have been advising schools to ensure that drinking fountains and taps are flushed after school holiday breaks as well as each morning.”