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Appendix 1: Terminology in the DWSNZ

Some of the terms used in the DWSNZ are explained below, either because the word or phrase is not commonly used, or because an understanding of the term is important for implementation of the NES.

Community drinking water supply: Water supplies consist of the three components discussed before: source, treatment plant, and distribution system. Community water supplies are reticulated (ie, supplied by pipe networks) public- or privately owned drinking-water supplies connecting at least two buildings on separate titles and serving at least 1500 person days a year (eg, 25 people at least 60 days per year).33 Supplies of fewer than 1500 person days a year can be registered as community supplies, but do not have to be. Community supplies are registered by public health units once they become aware of a supply’s existence.

Determinand: A constituent or property of the water that is determined, or measured, in a sample. The reader may find the word “contaminant” easier to understand than “determinand”, and this replacement is made in this guide. The word “determinand” is used in the DWSNZ to:

  • allow a single term to be used to cover, microbiological, chemical, and radiological constituents, and physical properties of a water

  • to avoid the connotation of pollution of the water through the use of the term “contaminant”, because many determinands are naturally-occurring and are not present because of pollution (eg, calcium).

Potable water: Water that is safe to drink because monitoring that meets the requirements of the DWSNZ has shown it not to contain any contaminants that exceed their MAV more frequently than is allowed by the DWSNZ.

Wholesome drinking water: This is water that has been shown to be potable, and in addition does not contain contaminants that make it taste, smell or appear unpleasant (the aesthetic properties of the water). Consumers readily identify problems with taste, smell or appearance of a water. Unless these water quality concerns are addressed, consumers may seek their own solution to obtaining acceptable water, which may result in their drinking palatable, but unsafe, water, eg, untreated water drawn from a spring that is not properly protected from pasture run-off.


33 This definition may include a supply owned by an individual if that person supplies water to one or more other buildings they do not own. Water suppliers are self-suppliers when owning a water supply that is exclusively used to supply water to one property that they also own, or to one or more buildings they also own.