Plumbing or drainage work on your property

This page has information on the approvals you need to carry out plumbing or drainage work in wet areas in your property within a building control area in the Northern Territory (NT).

Wet areas are rooms such as a bathroom, toilet, ensuite, powder room or laundry.

Your building project will fit in one of the following categories:

works not considered plumbing and drainage work
plumbing and drainage work that does not involve another building work
plumbing and drainage work that involve other building work.

Building work means work for or in connection with the construction, demolition or removal of:

a building, or
plumbing or drainage services, whether connected to a building or not.

This does not include plumbing or drainage services managed by the Power and Water Corporation, as laid out in the Power and Water Corporation Act 1987.

Work on multi-storey construction

If your building or plumbing work involves multi-storey construction, you may need different approvals.

This includes commercial buildings, apartments or townhouses.

For more information, talk to a registered building certifier.

Always use a licensed and registered plumber

You should always use a licensed plumber for plumbing work, including work to fixtures and fittings, whether or not you need a plumbing certificate.

A licensed plumber checks plumbing work and installations against current plumbing codes and standards.

To find a licensed plumber, go to the Plumbers and Drainers Licensing Board website.

Certifying plumber or drainer

A certifying plumber or drainer is a licensed plumber who is also registered with the Building Practitioners Board.

They can issue your plumbing and drainage work a certificate of compliance when it is done.

For the guidelines of the works NT-licensed plumbers and drainers can do under their licenses, email BAS@nt.gov.au.

To find a registered certifying plumber or drainer, go to the Building Practitioners Board website.

Keep building work documents safe

Keep all your building work documents, such as plumbing certificates and inspection reports.

You may need these to support the value of your property if you decide to sell it.

Work not considered plumbing or drainage work

These types of work are considered minor maintenance works, and they do not involve any alteration to the building, drainage or plumbing system or structure.

Building regulations do not apply and they can be carried out without a building permit.

They do not require you to notify the Director of Building Control once completed.

Types of work	Description of works	Notes
Minor maintenance, repairs and like-for-like replacements, like a bath for a bath	Non-testable backflow prevention devices Components of a fire hydrant system or fire hose reel Existing tapware A new bath to replace an old bath Basin to replace a basin Domestic water filter cartridge Shower head or hose Water closet cistern outlet and inlet valve.	These are works that do not require any alteration to the building, drainage or plumbing system or structure, as well as the layout design. They also does not include modifying in-wall pipework or tapware.
Repair of leakage in plumbing system	In-ground/ in-wall In-ceiling water leak.	Works that do not require any alteration to the building, drainage or plumbing system or structure.
Unblocking of toilets, showers or other plumbing fixtures		Mechanical tools can be used and do not need certification or notification.
New joinery work	New cabinets and benchtops, if there is no extension or inclusion of new plumbing work.	These works must have no changes to the original layout. Any changes to the layout design will require a building permit.
Shower screen	Installing a new or replacing an existing shower screen.
Retiling an existing wet area	Replacing small areas of damaged tiles.	If your work involves removing and replacing tiles, it is recommended that you engage a professional. This will help avoid damaging the waterproof membrane that protects the floor and walls.

Plumbing and drainage work that does not involve other building work

Certain plumbing or drainage work does not require a building permit and occupancy certification.

The work must be certified by an NT-licensed certifying plumber or drainer.

A notice of completion and Certificate of Compliance (plumbing and drainage works) must be provided to the Director of Building Control within 7 days.

Get the Certificate of Compliance (plumbing and drainage works) form:

Type of work	Description of works	Requirements
Replacing existing water services within a building or property	There must be no new penetrations to existing structures.	Certificate of Compliance (plumbing and drainage works).
Wastewater Management System (WMS) over 2,000L/day		Mandatory notification of drainage work Site soil evaluation WMS documentation Certificate of Compliance (plumbing and drainage works) Performance solution report Performance-based design brief Read more about the WMS over 2,000L/day requirements.
Wastewater Management System (WMS) under 2,000L/day		Mandatory notification of drainage work Site soil evaluation WMS documentation Certificate of Compliance (plumbing and drainage works).
Installing or replacing solar hot water system	Limited to existing buildings only Does not exclude any alteration to roof structure If alteration to roof structure is required for installation, it will need a separate building permit.	Certificate of Compliance (plumbing and drainage works).
Replacing an existing single major component of a water heater	Replacing storage tank, or Solar collector, or Mounting frame.	Certificate of Compliance (plumbing and drainage works).
Removing and reinstating an existing solar hot water system	Not done in connection with or incidentally to other building.	Certificate of Compliance (plumbing and drainage works).
Realigning or replacing existing drainage lines	No alterations to existing structures such as cutting or removal of slabs or floors.	Mandatory notification of drainage work Certificate of Compliance (plumbing and drainage works).
Replacing any external sanitary drainage		Mandatory notification of drainage work Certificate of Compliance (plumbing and drainage works).
Installing a new water supply to an existing building		Certificate of Compliance (plumbing and drainage works).
Replacing a major component to an existing onsite wastewater treatment system	Failed tank replacement.	Mandatory notification of drainage work Certificate of Compliance - Wastewater Management System Design/Installation Certificate of Compliance (plumbing and drainage works).
Replacing existing effluent disposal areas	Absorption and/or transpiration beds and drains.	Mandatory notification of drainage work Certificate of Compliance Wastewater Management System Design/Installation Certificate of Compliance (plumbing and drainage works) Site soil evaluation.
Installing or replacing of an existing grease trap or arrestor		Mandatory notification of drainage work Certificate of Compliance (plumbing and drainage works).
Installing or maintenance works for a temperature control device	Thermostatic Mixing Valve (TMV) Tempering mixing valve. Only licensed advanced tradesmen who have endorsement to do thermal mixing valve are allowed to carry out the work.	Certificate of Compliance (plumbing and drainage works).

Wastewater management systems over 2,000L/day

If a wastewater management system (WMS) is designed for flow over 2,000L/day, it requires a performance solution report that shows the method of construction that complies with the performance requirements.

The performance solution must be designed by an NT-registered certifying engineer (hydraulic).

An NT-registered certifying plumber and drainer can carry out and certify the construction.

A performance-based design brief (PBDB) must also be provided to the Director of Building Control.

This is a report that defines the:

scope of work for the performance-based analysis
technical basis for analysis
criteria for acceptance of any relevant performance solution as agreed by stakeholders.

Read more about preparing a PBDB in the performance solution process guidance document.

Plumbing and drainage work that involve other building work

You must engage a building certifier for the works listed below. Certifying plumbers and drainers cannot issue a building permit or occupancy certification for these types of work.

A building permit is required for certain plumbing and/or drainage work carried out in the building control area.

There are serious penalties for the owner and others for doing building work without a building permit. Any person that knows about or helps another in doing work without a building permit may also be held accountable.

Read about engaging a registered building certifier and getting a building permit.

Type of work	Example
Putting in or taking out partitions or walls	Dividing a room to create a separate area Removing a partition to incorporate a toilet in a bathroom Enclosing an outside laundry.
Breaking into or altering the walls or floors in wet areas	Putting new plumbing through or into the wall or floor Installing or increasing the size of a window or door Adding or removing a wall.
Installing new fixtures or fittings where they do not already exist	Putting in a new bath Putting in a shower where there used to be a bath.

Contact

For more information or to notify about works, contact the Director of Building Control:

bas@nt.gov.au
08 8999 8985

Level 1 Energy House
18 - 20 Cavanagh Street
Darwin NT 0800

GPO Box 1680
Darwin NT 0801

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