Standards and Testing

Watercare treats its water to A-grade quality.

The company manages its system to comply with the appropriate standards for bulk water supplied to Auckland, and for wastewater discharged at the Mangere Wastewater Treatment Plant.

Information on the Drinking Water Quality for NZ 2000 that are set by the Ministry of Health is included here.

Who sets the standards for drinking water? 
The Ministry of Health sets the New Zealand Drinking Water Standards 2000 (NZDWS) Implemented Jan 2000. They include some stringent new requirements on monitoring for turbidity (water clarity), which must be met by all bulk water suppliers by 2005.

The NZDWS are not mandatory but this situation may change with an impending review of the Health Amendment Act. However, the Ministry of Health already requires that new drinking water sources must meet the NZDWS.
 
How well does Watercare meet the standards? 
All of Watercare's supplies comply with the requirements of the New Zealand Drinking Water Standards 2000. All of the treated water from all of Watercare's treatment stations meets the standards. The sophisticated membrane filtration system at the Waikato plant means that treated Waikato River water has been approved by the Ministry of Health. It is the only Watercare plant that already complies with all of the 2005 requirements.

How do we compare with other countries and cities? 
The NZDWS, like most European and North American Standards, are based on those recommended by the World Health Organisation. Each country introduces modifications to suit local conditions. Being an agricultural country, New Zealand places greater emphasis on detecting and treating of agricultural chemicals.

In general, there is little difference in the raw water sources servicing New Zealand cities. In overseas cities however, raw water sources can often be rivers flowing through large industrial and residential centres or large open reservoirs that are also used for recreational activities including pleasure craft.
 
How often is raw water tested? 
Generally, raw water in the dams is tested monthly unless a potential problem, like algae growth, is detected. Tests are then carried out weekly or daily. The river water is tested weekly, although continuous monitoring at the intake site warns of any significant change to the raw water quality.

What is looked for and with what results? 
Raw water analysis detects a wide range of components but focuses on those that would affect the treatment process or be harmful to health, such as algae, faecal coliforms, giardia and cryptosporidium.

Treatment is adjusted constantly to meet the quality of the incoming raw water and water supply safety measures, such as temporary shut off of a particular supply, are taken when required. In 2000 this happened when blue/green algae contaminated the Waitakere dams and in 2002 when a truck carrying chemicals overturned in Hamilton, potentially affecting the Waikato River supply.
 
How is the raw water treated? 
The water from the dams goes through a three-stage process: clarification, sand filtration, and chlorine disinfection.

The Waikato River water passes through four-stages: clarification, membrane filtration, granular activated carbon filtering, and chlorine disinfection.
 
How often is it treated? 
Some components are tested for continuously, others at less frequent intervals according to the significance of the component. Water from the Waikato River Treatment Plant is monitored continuously for turbidity (water clarity), pH saline, residual chlorine and fluorine concentration.
 
What is looked for and with what results? 
Treatment ensures that all Auckland's water meets the NZDWS requirements. Not only that, all of Watercare's treatment plants have an A-grade rating from the Ministry of Health for both treatment
plants and its distribution system, they are among the highest ratings in the country.

The drinking water standards are like a warrant of fitness; they are tested for at a regular, pre-determined frequency. 

What about other potentially harmful organisms in the water? 
It is practically impossible to test water for all the hundreds of conceivably harmful organisms that might be present. There is no possible health risk from any chemicals or harmful organisms in the treated water however. The treatment system ensures this. Any unrecognised chemicals, chemical compounds or organisms are likely to be of the same chemical or microbiological structure as the recognised ones, and are therefore treated in the treatment process.

What is the position with oestrogen? 
Oestrogen in water is predominantly an environmental issue. It is widely acknowledged that oestrogen in water does not have a direct impact on human health.

Nonethless, oestrogen is in a group of endocrine disruptors that is dealt with effectively by the Waikato River Treatment Plant process. Although many tests have been carried out, no oestrogen has ever been detected in samples from the intake site. 

What happens in an emergency? 
There are many points where water flow can be shut off - all the way from raw water intakes to just before the consumer. Health authorities are adamant that, in the event of an emergency, stopping supply is a last option - it is preferable to continue supply and issue health notices regarding quality.