Drinking water flowing to almost one in six New Zealanders has either not reached the Ministry of Health (MOH) standards or escaped testing during 2007/08, as per the ministry.

A review has been released on the drinking water quality which was conducted by the Institute of Environmental Science and Research.

91 percent of the people receive their water from a town supply and the rest of them have their own supplies- generally from their roof or a bore- unmonitored.

8 percent New Zealanders are on town supplies which have not passed testing for bacteria and viruses.

The principal public health engineer of MOH, Paul Prendergast said that the indicator which was tested for was the bacteria E. coli.

"E. coli in the water doesn't necessarily make you sick, although some E. coli can. It's just telling you you've got faecal matter in the waterway and if that faecal matter is from a sick animal with a waterborne disease then that could pass through to humans."

15 percent of the town supplies have not passed testing for cryptosporidium, which can lead to an upset stomach.
(Additional reporting by Kavita Toor)