Drinking-water compliance increases significantly

Drinking-water compliance increases significantly

New Zealanders have greater access to safe drinking-water according to the Ministry of Health’s latest survey of drinking-water quality.

The Annual Review of the Microbiological and Chemical Quality of Drinking Water 2002 ­– released by the Ministry today – showed 78 percent of New Zealanders accessed safe drinking-water last year.

This reflected an eight percent rise in the proportion of the population supplied with drinking-water that complied bacteriologically with the new drinking water standards for New Zealand 2000 (DWS2000) compared with the 2001 compliance figures.

The population served by complying zones climbed to approximately 2.72 million in 2002, an increase of approximately 300,000.

The Ministry’s Principal Public Health Engineer Paul Prendergast says the latest survey does not mean the rest of the population necessarily receive unsafe drinking-water, but that we cannot demonstrate effectively the water is safe.

"Most of the supplies that didn’t comply were from private domestic supplies or small rural supplies that were either not monitored or were monitored inadequately."

In general, the new standard’s monitoring requirements are tougher for supplies serving larger populations but less stringent for the smaller supplies.

Mr Prendergast says one of the pleasing aspects of the survey, which covered 3.5 million New Zealanders, is that school compliance has nearly doubled. However, he says there still remains significant room for improvement.

In 2002 57 percent of school supplies were monitored, up from 47 percent in 2001. 107 schools or 17 percent complied with the bacteriological criteria, up from 55 schools (nine percent) the previous year.

"The microbiological quality of drinking-water is an important factor in maintaining public health. If we fail to maintain high microbiological standards there is the potential for outbreaks of disease,” said Mr Prendergast.

Contaminated water can spread a range of gastrointestinal disease. These are caused by bacteria, viruses, or protozoan parasites including Campylobacter, Salmonella, E. coli O:157, Giardia, Cryptosporidium, Norwalk virus and other enteric viruses. Other diseases can include hepatitis A and dysentery.

The 2002 review is the second report using the new drinking water standards and the first to include both chemical and microbiological compliance.

The microbiological health risk was assessed using two main criteria: E. coli and Cryptosporidium. The chemical health risk for selected supplies was assessed with respect to those specifically-assigned chemical determinands (P2 chemical determinands) for which monitoring was required.

Copies of The Annual Review of the Microbiological and Chemical Quality of Drinking Water 2002 are available on the Ministry of Health website www.moh.govt.nz in the Publications section

Questions and Answers

Where does the information in the report come from? Public health units at each District Health Board complete a questionnaire on the performance of the water suppliers. The results are verified with the water suppliers before they are sent in.

What is a registered water supplier? The Ministry of Health maintains a register of all water suppliers that it is aware of that serve 25 people or more for at least 60 days each year. Water suppliers fall into two groups: local authorities, and private organisations or communities responsible for the operation of their own drinking-water supplies. The register of suppliers includes town and rural water supplies, food outlets, schools, marae, sports clubs, hospitals, hotels, motels and camping grounds. In 2002 the register contained 2060 water treatment plants and covered an estimated 87.5 percent of New Zealand’s population.

Why is the Ministry of Health so concerned about drinking-water quality? The microbiological quality of drinking-water is an important factor in maintaining public health. Failure to maintain high microbiological standards by not managing bacteria and viruses leads to the potential for outbreaks of disease, if the water becomes contaminated by pathogens that the community has not become immune to. Although the local community may become acclimatised to the presence of micro-organisms that are regularly present in the water and develop a resistance to them, visitors to the area may be affected.

What other activities are underway to improve the quality of drinking-water? The Annual Review of the Microbiological and Chemical Quality of Drinking-Water in New Zealand is part of an organised campaign that started in 1992 to improve the quality of the country's drinking-water. Other ways to develop the safety of the nation's drinking-water developed since 1993 are: • The Drinking-Water Standards for New Zealand 1995 and 2000 • External surveillance by Health Protection Officers • A register of Community Drinking Water Supplies • Public Health Grading of Community Water Supplies • An Annual Report on the Microbiological Quality of Drinking Water Supplies in New Zealand • Guidelines for Drinking Water Quality Management in New Zealand • Register of Ministry of Health Recognised Laboratories for drinking-water compliance testing • Laboratory accreditation requirements for all testing laboratories • National electronic water quality database (WINZ) • Public Health Risk Management Plans for drinking-water supplies.

These activities have been very successful in improving the safety of public water supplies but the Ministry now believes it has reached the limit of what can be achieved with non-regulatory intervention. We recently proposed some amendments to the regulatory framework – the Health (Drinking-Water Supplies) Amendment Act.

Who is responsible for school drinking-water standards? The safety of school drinking-water supplies is the responsibility of each school’s Board of Trustees. However where a major upgrade is necessary, such as a new bore, the Ministry of Education will undertake the work under its capital works programme. The Ministry of Education has also updated its Health and Safety Code and refers to the drinking-water standards.

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