Plumbing can be divided into two general areas - sanitary plumbing, and everything else.
New Zealand was the first country in the world to give legal recognition to the specific risks and
dangers inherent in many aspects of the plumbing trade. In 1912, plumbing became the first trade to be
registered in New Zealand. An Act of Parliament made it illegal for anyone other than a qualified and
registered person to undertake work classified as sanitary plumbing. Later, aspects of gasfitting and
drainlaying also became registered work.
The definitions of what constitutes plumbing, gasfitting and drainlaying, are very important, but these
definitions change slightly from time to time in response to changes in the industry. The definitions quoted
here are from the current version of the - The Plumbers, Gasfitters and Drainlayers Act, 2006.
The definition of Sanitary Plumbing is as follows:
Meaning of sanitary plumbing
- In this Act, unless the context otherwise requires, sanitary plumbing means:
- the work of fixing or unfixing any sanitary fixture or sanitary appliance, or any associated fittings
- the work of fixing or unfixing any trap, waste or soil pipe, ventilation pipe, or overflow pipe connected
with or intended to be connected with or accessory to any sanitary fixture or sanitary appliance or any
drain (whether or not the sanitary fixture, sanitary appliance, or drain is there when the work is done):
- the work of fixing or unfixing any pipe that
- supplies or is intended to be a means of supplying water to any sanitary fixture or sanitary appliance
(whether or not that sanitary fixture or sanitary appliance is there when the work is done); and
- is within the legal boundary of the premises on which that sanitary fixture or sanitary appliance is
or will be installed (whether or not that sanitary fixture or sanitary appliance is there when the work is
- generally all plumbing work associated with any sanitary fixture or sanitary appliance
Therefore the legal definition of sanitary plumbing encompasses all water pipes within the boundary of a
property, including any fixtures and fittings within that system. This includes hot water systems, valves
and devices used to control pressure and temperature and to prevent backflow.
Foul water collection and disposal systems are also included in this definition. This includes pipes,
vents and devices to control pressure fluctuations and foul air movement.
Why is this?
There are three main ways in which faulty plumbing can cause serious health and safety issues, two
of them fairly obvious, the third less so.
- Risk of disease
Necessity for a fresh and clean water supply
- Water contaminated with human waste and other noxious substances are a breeding ground for a multitude of
diseases, from cholera to SARS. We refer to such contaminated material as foul water. It is self evident
that the safe collection and disposal of these products is fundamental to preventing any outbreak and spread
of these many illnesses.
Hazards associated with producing hot water
- Fresh and clean water, known technically as potable water, is a fundamental necessity for healthy life.
It is particularly important when people are crowded together in communities. The contamination of communal
drinking water by disease or chemical pollution can very quickly create serious problems if transferred
through a public, or shared, water supply. Because our water systems are mostly interconnected and come
from common sources, any contamination can be rapidly carried from its source through to the rest of the
community supply. Accidental cross-connection, or the forced mixing of contaminants by pressure
differential, is preventable by the correct layout and separation of pipe systems, and the incorporation of
back flow prevention devices. Plumbers have the training and experience to identify potential risks and
determine the appropriate solutions.
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- Hot water systems, especially storage systems, are intrinsically dangerous if installed incorrectly. A
mixture of pressure and temperature can create a variety of hazards from scalding (by either hot water or
steam), or in extreme cases, explosion (illustration below). Although systems are usually controlled by
a thermostat, these commonly fail. A range of other devices must be installed to monitor and protect the
system, both from over-pressure and over-temperature.
What plumbing can an unlicensed (unqualified) person undertake legally?
The Plumbers, Gasfitters and Drainlayers Act allows unqualified
persons to carry out work which is outside the legal definition of sanitary plumbing, although some of this
work may be restricted by other legislation and/or insurers. The Plumbers, Gasfitters and Drainlayers Act
2006 excludes certain work from the definition as follows.
Despite subsection (1), sanitary plumbing does not include
- the work of fixing or unfixing any sanitary fixture or sanitary appliance that is installed in any
ship, boat, aircraft, or vehicle, or any plumbing work associated with any of those sanitary fixtures or
sanitary appliances; or
- the work of fixing or unfixing a bedpan washer, a bedpan steriliser, a dishwasher, or a washing
machine in any case where the fixing or unfixing of waste pipes or of pipes supplying or intended to
supply water is not involved; or
- the work of fixing or unfixing a pipe for reticulating water in any central heating or cooling system
downstream of a testable backflow prevention device that is used exclusively for that central heating or
cooling system; or
- the work of repairing or replacing taps, ball valves, tap washers, or plugs; or
- the work of fixing or unfixing any shower that is installed over a bath and that is supplied with
water through the bath taps
This means that work an unlicensed person (including a home owner) can undertake, includes:
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- Maintenance of taps and tap washers. If the work does not involve fixing and unfixing of water supply
pipes, any person may replace tap washers and repair taps and valves.
- Installing/replacing spouting and downpipes. Any work above ground may be done by unqualified persons,
but note that most below-ground work must only be done by a Registered Drainlayer.
- Roof work. Most roof work does not require registration currently, but this may change as certain
sections of the Building Act relating to licensing of builders come into force.