Plumbers, Gasfitters and Drainlayers Board

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What is drainlaying and who can do it?

Effective and correctly installed drainage systems play an important role in protecting public health and maintaining a pollution-free environment. If foul water is not correctly disposed of it can pose a significant risk both to the community at large and to our environment.

Drains are underground pipes which carry foul or surface water (stormwater) and enter either an onsite waste water disposal system (septic tank) or a sewer which is likely to be controlled by a territorial authority (district council).

Drainlaying work is generally undertaken inside a legal boundary though this may not always be the case. Drainlaying work however does not include pipes in the control of the Crown or a local authority. Drainlaying also does not include an open jointed or perforated drain for collecting and removing ground water.

Central to a well installed and well maintained drainage and disposal system is a certifying or licensed drainlayer. To become a certifying drainlayer a person will be in training for at least four years.

What is drainlaying?

Drainlaying is any work involving the installation, alteration or repairs to a drain, including the fixing or unfixing of a drain to an onsite wastewater system (septic tank) or any trap.

All drainlaying work must comply with the Building Code and where a building consent is required, the work must be checked by the building inspector from the building control authority in your area (your local council). A code compliance certificate cannot be issued until the work has been signed off by the building inspector.

A certifying drainlayer is responsible for the testing, verification and the supervision of tradesman drainlayers, Journeyman drainlayers, limited certificate (trainee drainlayers) and exempted persons.

People who are not registered as a drainlayer are able to clear blocked drains, but only if this does not involve altering or repairing the inspection pipe or ventilation pipe in any way.

Who can undertake drainlaying?

A certifying or licensed drainlayer can lay, alter, reconstruct, extend, repair and open up drains and associated traps and connect drains up to and away from waste water treatment stations (septic tanks).

If you require new drains to be installed or existing drains altered you must engage a person who holds a current drainlaying licence and is legally entitled to carry out this work (remembering that this person may be required to operate under supervision).

The most common problem that occurs with a drain is blockage. Blockages occur for a number of reasons; foreign matter dropped down the drain, tree root intrusion, overloading, collapse, misalignment. A blockage in a drain will usually require the services of a tradesperson who can clear the blockage. Clearing a blocked drain is not regarded as drainlaying, however, anytime a drain is opened up, altered, reconstructed, extended or repaired then that work can only be legally undertaken by a licensed drainlayer.

Similarly, people believe the installation of the outfall from an onsite waste water system not to be drainlaying. However, this is incorrect and has now been proven in law when a non-registered person installed drip lines from an onsite waste water installation.

Authorisation type
License category 1st Tier | Certifying Drainlayer
The highest qualification available. These people are qualified and registered. They are responsible for ensuring both their own work and the work of anyone they supervise is done competently.

2nd Tier | Tradesman Drainlayer
These people are qualified and registered and usually work independently.  However, a nominated certifying tradesperson (supervisor), is ultimately responsible for ensuring that the work is done competently.

3rd Tier | Journeyman Drainlayer
These people have completed a trade qualification but have not passed the Board's licensing exam.  They are registered and authorised.  

Training | Limited Certificate Trainee Drainlayer
These are people who are working towards becoming qualified. They can do the work but must be supervised by a certifying person who is ultimately responsible for ensuring the work is done competently.
Exemption for drainlaying under supervision Exemptions
These people are not registered and don't have a full qualification, but they can do drainlaying work provided they are supervised by a certifying person, who must ensure that the work is done competently.

Contact the Plumbers, Gasfitters and Drainlayers Board

Phone: 0800 743 262, Email:, Post: PO Box 10655, The Terrace, Wellington 6143
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