Management of drinking-water in New Zealand can be broken into three main parts:
The environment - The source of the water, either from below ground of from surface catchments, is primarily governed by the Resource Management Act 1991.
Water suppliers - This involves obtaining the raw water from the environment, followed by storage, assessment, treatment and distribution to consumers. Regulation of this system of abstraction and supply was previously managed through voluntary regime. However the Act now regulates this system of treatment and distribution which requires water suppliers to contribute towards protecting from contamination all sources from which the drinking-water supplier takes raw water.
Storage and Distribution - Storage and distribution of water in tanks and pipes within buildings up to the point of use (generally a tap) is governed by the Building Act 2004. This Act takes over responsibility for water once it leaves a public networked supply and enters the building-owner's property (usually at the water toby) and also applies to water distributed within a building from its own self-supply (e.g. a roof tank or bore).
The schematic diagram below illustrates the various Acts involved with the provision of safe, potable drinking-water.