Informative alert

Key information about water services legislation changes

The Local Government (Water Services) (Repeals and Amendments) Act became law on 26 August. We’re updating our website to reflect the new legislation by mid September. For information on key changes, visit: Key information about water services legislation changes

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Hinekōrako Outage - Saturday 27 September 7am-11am

Find out how to contact us during this time: Hinekōrako outage

Water properties

Explore key terms and concepts that describe water’s physical properties.

pH

pH is a measure of the acidity or alkalinity of a substance. It is measured on a scale from 1-14. The pH of drinking water should ideally be between 6.5 and 8.5. Some disinfectants are pH-dependent and may not work as efficiently if the pH balance is not at their recommended level. 

Plumbosolvency

Plumbosolvency describes the ability of water to absorb lead and other metals. In New Zealand, most drinking water is plumbosolvent. This means the water can dissolve small amounts of metals it may come into contact with, such as lead and copper in plumbing fittings (like pipes and taps). Both drinking water suppliers and consumers need to take steps to protect against the risk of contamination by lead and other metals. 

To reduce any risk use only cold taps for water for drinking and cooking. Flush these taps for 10 seconds each morning to draw fresh water through the taps. If the property has been unoccupied for more than 48 hours flush for two minutes.

To reduce any health risk, you should flush at least a mugful of water from your drinking-water tap each morning before use, and after any extended absence from your property.  

Read more about plumbosolvency.

Turbidity

Turbidity is the haziness or cloudiness of water caused by suspended particles and dissolved organic matter. Turbidity reduces the effectiveness of many treatments that make water safe for drinking. It can block filters designed to remove pathogens and small particles from water, decrease the effectiveness of ultraviolet treatment and lower the effectiveness of chemical disinfectants such as chlorine. Turbidity is measured in Nephelometric Turbidity Units, commonly referred to as NTU. 

UV transmittance

Ultraviolet (UV) transmittance is a measure of how well UV light passes through water. It is measured as a percentage (%UVT), with the higher the number the more effective UV treatment is. Most UV systems will shut off automatically if UVT is too low. If you have end-point treatment and the system is not validated, there is a risk that unsafe water may be produced when water is turbid and has low UVT.  

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