Drinking water in many rural schools and hospitals is failing to meet minimum safety standards, with some recording high levels of faecal contamination and heavy metals.
The Health Ministry's annual review of drinking water quality – carried out by the Institute of Environmental Science and Research – shows nearly one in four New Zealanders (712,000 people) were supplied with drinking water in 2007-08 that was substandard or untested.
Of the 590 schools with their own water supplies, 83 per cent had unsafe levels of bacteria and none were treated to a high enough level to protect children from tummy bugs caused by giardia and cryptosporidium infections. Nearly 30 per cent were not even tested.
All 10 hospitals and health services not connected to municipal supplies met the standard for bacteria levels in drinking water, but most still carried some risk of giardia or cryptosporidium.
There were 15 outbreaks of waterborne disease during the year, affecting 205 people, but this is thought to be a fraction of the number of people infected as a result of untreated or contaminated water supplies.
Officials estimate that about 35,000 people a year are affected by waterborne diseases, with most going unreported.
Chief public health engineer Paul Prendergast said overall compliance had increased since the previous year, with 3 per cent more of the population having access to good quality drinking water.
However, the Health Ministry was concerned by the increase in the number of people exposed to "unacceptable risk" by suppliers failing to fix problems with faecal contamination or warn the public.
The report singles out 38 local authorities that neglected to "adequately protect consumers at times when the drinking water was known to be contaminated". Another 78 suppliers simply stopped testing for faecal contamination, apparently in an attempt to "avoid scrutiny".
"We're following all these cases up," Mr Prendergast said.
"Sometimes it could be because of lack of resources, sometimes it appears to be a habit of blaming a bad result on lab error. In some cases, they may have made some corrective action, but not done enough to meet our standards."
Generally, smaller rural suppliers were less likely to be compliant, he said.
Martinborough and Lake Ferry Camping Ground water supplies were among those that failed to comply, with "excessive E. coli transgressions" of unknown origin.
Martinborough's water was also found to have traces of the cancer-causing chemical cadmium.
South Wairarapa District Council chief executive Jack Dowds said the council's own testing had shown water quality in the region was generally of "very high quality".
"We do have a problem in Martinborough with manganese [a mineral], which means the water can't be treated with chlorine and we're currently drilling for other bores."
Cadmium contamination was "not unique to South Wairarapa", he said. Acidic water could dissolve small amounts of lead and copper in older taps. This could be avoided by running the tap for 10 seconds to flush the taps.
Green MP Sue Kedgley said water quality was a matter of public health and cash-strapped local authorities urgently needed Government support. "Some of these smaller local authorities say it would bankrupt them to treat their water to the standard required."
* Best water supply: Hutt Valley 100 per cent poo-free
* Worst water: Gisborne just 3 per cent of residents get water proven to be free of faecal contaminants
* 83 per cent of Kiwis' drinking water has safe bacteria levels
* 76 per cent of the population mainly in big cities have water that meets the "gold standard'' of protozoal-compliance (i.e. guaranteed not to give you cryptosporidium or giardia)
* Only 17 per cent of tested schools with their own supplies met minimum safety standards
* 156 water zones including 80 run by councils lost bacteriological compliance in 2007-08
* 78 suppliers stopped monitoring for faecal contamination
* 36 local authorities failed to act when water was found to be contaminated.
- The Dominion Post
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