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