2003 drinking water survey
1 March 2005
Ministry of Health releases 2003 drinking water survey
While most New Zealanders continue to have safe drinking water, some smaller communities have either water that still needs improvement or better monitoring to prove its safe, a Ministry of Health survey of drinking water quality has revealed.
In the Annual Review of the Microbiological and Chemical Quality of Drinking Water 2003 ? released by the Ministry today ? microbiological health risk was assessed using two criteria: E coli bacteria and the water-born protozoa Cryptosporidium.
During 2003, water supplies to 71 percent of New Zealanders complied with E. coli standards, a two percent improvement since 2002. There was a 73 percent compliance with the treatment plant protozoan requirements. The report notes the protozoan compliance figure dropped from about 81 percent in 2002, but that was almost entirely due to problems at a Waitakere plant. Those problems have subsequently been resolved.
About 1.1 million New Zealanders were supplied with drinking water during 2003 that failed to comply with the current DWS2000 standards.
Many of the causes for this non-compliance centred on levels of E. coli or a failure by suppliers to take proper action, including monitoring, after it was found. Some didn't use accredited labs, or supplied water from an unregistered source.
The Ministry?s Principal Public Health Engineer Paul Prendergast says this latest survey does not necessarily mean that 1.1 million people peopled received unsafe drinking water during 2003. It simply means water suppliers did not demonstrate the water was 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," he says.
"In general, large metropolitan areas and provincial cities are served by supplies that comply with microbiological standards."
While water quality standards are the same throughout New Zealand, monitoring requirements are stricter for supplies serving large populations than those for smaller populations.
The review reveals some school drinking supplies have significant room for improvement. During 2003, only 55 percent of schools with their own water supplies conducted some form of bacteriological monitoring, two percent fewer than the previous year, and of those, only 14 percent complied with bacteriological criteria within the standards, a three percent reduction since 2002.
"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.
Copies of The Annual Review of the Microbiological and Chemical Quality of Drinking Water 2003 are available on the Ministry of Health website www.moh.govt.nz/water
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 2003 the register contained 2,223 distribution zones and 2,169 water treatment plants and covered an estimated 87 percent of the New Zealand population. The microbiological and chemical quality of drinking water was assessed against the DWS2000 standards, using a survey of all treatment plants and distribution zones.
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 The development of the Drinking-Water Standards for New Zealand 2005 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. Further information on the proposed legislation is on the Ministry website: www.moh.govt.nz/water
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.