More than one million New Zealanders are regularly drinking water that is not demonstrably safe to drink, an issue that makes tens of thousands of people sick each year and would cost billions of dollars to address, Government documents show.

Among the suppliers known to be failing their legal requirements are schools, a hospital, a Government agency, and numerous local authorities.

A series of Cabinet papers regarding the Government's planned reform of the drinking water sector, as well as years of compliance records, show the existing system is dysfunctional, with basic data unavailable and public health left in the hands of small community groups, private companies, and under-resourced councils.

One international drinking water expert said an outbreak similar to the one that afflicted Havelock North in 2016 was inevitable, and wide-ranging changes needed to be made for New Zealand to catch up with some other developed countries.

The Government estimates around 34,000 people become sick every year from their drinking water, and says around 900,000 people drink water that is not adequately tested for two contaminants known to be common causes of sickness outbreaks internationally: Cryptosporidium and giardia.

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It also believes around 800,000 people drink water that is not regulated at all. The overwhelming majority of those supplies will not be meeting drinking water standards, meaning it is unclear if the water is safe.

Changes to the drinking water system have been planned since the 2016 outbreak in Havelock North, which was tied to at least four deaths and made thousands of people sick. It was the largest outbreak of waterborne campylobacteriosis recorded anywhere in the world.

An inquiry following the outbreak, which included evidence from a panel of international experts, pointed to major failings in New Zealand's drinking water infrastructure and made numerous recommendations for reform, including an independent drinking water regulator.

CHLOE RANFORD/LDR New Zealand's drinking water system is dysfunctional.

The Government agreed to set up such a regulator last year, which is expected to be operational in 2021.

The regulator - Taumata Arowai - has a tough task ahead. Under the proposed changes, regulation will be expanded from around 800 registered suppliers currently to several thousand, many of them tiny networks supplying fewer than 25 people which have never been required to meet health standards.

The exact number of those supplies is unclear; despite a requirement that all networked water supplies be registered, the Government acknowledges a large number are not. One estimate provided to the Government says those small networked supplies could number anywhere between 1130 and 5650.

The regulator will also need to address the history of flagrant non-compliance among the supplies already regulated.

The law is currently enforced by the Ministry of Health, which has never taken enforcement action against a drinking water supplier, despite its own compliance records showing more than 700 instances of non-compliance with the Health Act since 2011.

Under current rules, supplies serving more than 100 people need to comply with the Health Act, which requires doing things such as regular quality testing, recording and dealing with complaints, and having a water safety plan.

They also need to take "all practicable steps" to meet drinking water standards, which cover three types of contaminants: bacteria, protozoa, and chemicals.

The most recent available data, covering the year 2017 to 2018, shows nearly one in three supplies were in breach of the Health Act, and around two thirds were not meeting the drinking water standards. Among those breaching the Health Act were two primary schools, a hospital, a Government agency, and numerous councils.

The rate of non-compliance has been steadily increasing. In 2014, 7 per cent of supplies breached the Health Act; it is now 32 per cent, in large part due to the broadening of standards to include smaller supplies.

The lack of enforcement action was a concern, said Dr Colin Fricker, a UK-based drinking water expert who was part of the scientific panel for the Havelock North inquiry.

"The real issue is that [the water] is very poorly monitored and regulated compared to most other developed countries, therefore we don't really know how good or how bad it is," he said.

"If you break the rules, so what? Nothing happens. If you break the rules in the UK, you'd get fined millions, or the regulator would come in and say, you didn't do it, so we'll do it, at your cost."

He welcomed the establishment of a new regulator, but said that in itself was not enough to fix the issues; There needed to be more resource and expertise sharing between suppliers.

Large cities typically had good water quality, but he remained concerned about smaller areas, that were vulnerable to an outbreak similar to that which affected Havelock North.

"There will be another outbreak - hopefully it will be a small one, and there won't be any loss of life, but there are larger communities than Havelock North that are more at risk than they were, in my opinion," he said.

"It's just a question of many things going wrong at the same time, and then there will be another outbreak."

It echoed the overall findings of the Havelock North inquiry, which painted an often damning picture of the drinking water regulatory regime.

Its stage two report, released in 2018, described the Ministry of Health's enforcement policy and implementation as "inept", and said the inquiry was "unable to discern any leadership activity by the Ministry, at any time" in relation to Health Act breaches by drinking water providers.

"A lack of accountability underlies the current poor compliance levels prevalent throughout New Zealand," it said. "In many cases, these have continued for many years with no apparent sanction or accountability."

When asked by Stuff about its lack of enforcement, the Ministry of Health acknowledged it had never taken action against a drinking water supplier, but said doing so was not the only way to achieve compliance.

"Drinking water assessors always consider the need for compliance before enforcement and have found that education and persuasion achieve the best outcomes in cases of non-compliance," a Ministry spokeswoman said.

"For example, the failure to meet the monitoring requirements by missing the collection of a single water sample has minor public health significance and enforcement is not necessary."

Basic Failures

Because so many supplies are not regulated, it is unclear whether the water they provide is safe to drink.

The unregulated supplies providing drinking water to 800,000 people are likely to include schools, universities, airports, prisons, campgrounds, marae and papakāinga, according to one Cabinet paper. Many of those supplies will be managed by local authorities and government agencies.

Compliance records show the smaller a supply, the less likely it is to meet drinking water standards, suggesting it may be difficult to make thousands of newly regulated small suppliers meet the standards.

The latest compliance data shows that of the 493 supplies providing water to more than 100 people, around 157 failed to meet all the requirements of the Health Act, and 329 failed to meet all of the drinking water standards.

Inadequate testing was the main reason a supply breached the law: 146 supplies failed on this measure. The records do not show the extent of each failure, which could range from missing one test to not doing any testing at all.

Some supplies, however, were making basic failures. Among the most important contaminants to test for is E. coli, which can easily enter a supply in small quantities and cause widespread sickness, particularly in rural areas.

At least 22 suppliers did not test drinking water for E. coli at all. Among them was a primary school in rural Mid-Canterbury surrounded by dairy farms.

Drinking water assessors had showed less leniency since the Havelock North outbreak, which was why the number of supplies that failed monitoring requirements had increased over time, the Ministry of Health said. The law allows them to grant exemptions for monitoring failures if they think the reason is justifiable, an option they have been using less.

Around 30 supplies, together providing water to around 35,000 people, were deemed to be "failing to take appropriate action to protect public health after an issue was discovered".

The issues were not identified.

In most cases, these suppliers were local authorities. Six of them were in communities supplied by the Taupō District Council, and another six were supplied by the Clutha District Council.

Other suppliers that failed for this reason were the district councils of Whakatāne, Rangitikei, Carterton, Masterton, Tasman, Selwyn, Mackenzie, and Waitaki.

Repeat Offenders

Because compliance has been recorded since 2008, it is possible to track suppliers repeatedly in breach of their legal obligations.

There are several, but one notable offender is a Government agency: the New Zealand Defence Force. It runs five supplies at its training camps and bases, collectively supplying water to more than 10,000 people.

Records show it has consistently failed to comply with both the Health Act and the drinking water standards.

In 2018, all five of its supplies were not complying with the Health Act, with particular problems at its Waiouru camp.

The Waiouru supply, records say, did not have a current water safety plan, failed its monitoring requirements, and did not take appropriate action to protect public health after an issue was discovered. It was far from the first time; previous compliance records show the last time the NZDF's Waiouru supply met the requirements of the law was in 2012.

"[T]he NZDF has been working hard to upgrade both infrastructure and the administration of water at its camps and bases," a spokesperson said.

"Major upgrades to both Burnham and Tekapo water supplies have been finished and are in the final stages of commissioning. Planning is underway for upgrades at Waiouru and Linton. Upgrades take time, and the NZDF places the utmost importance on the safety and compliance of its water supplies and is prioritising this work."

The NZDF's water "is generally safe and free from contamination, but we have plans in place to deal with the unexpected," the spokesperson said.

Some moderately-sized townships routinely fail to meet the requirements of the Health Act, the drinking water standards, or both.

Among them is Feilding, population nearly 15,000, which has not complied with the Health Act or drinking water standards since at least 2013. Dannevirke, population 6000, last complied with the Health Act in 2015, and has not met the drinking water standards since 2010.