No — fitting a gas isolation valve under your hob is not a DIY job in New Zealand. Any work on gas installations, including fitting, moving, or replacing isolation valves, is classified as restricted work under the Gas Act 1992 and must be carried out by a licensed gasfitter. Doing this work yourself is illegal, potentially dangerous, and could void your home insurance.
Why Gas Work Is Restricted in New Zealand
Gas installations in NZ are regulated to protect people from the very real risks of gas leaks, fire, and carbon monoxide poisoning. The Plumbers, Gasfitters and Drainlayers Board (PGDB) is the authority that licenses and oversees gasfitters in New Zealand. Only a person who holds a current gasfitting licence issued by the PGDB is legally permitted to carry out restricted gasfitting work — and fitting an isolation valve on your gas supply line firmly falls into that category.
Under the Gas (Safety and Measurement) Regulations, any work that involves connecting to, modifying, or disconnecting from a gas installation is restricted. This includes:
- Installing or replacing an isolation (shut-off) valve on a gas line
- Connecting or disconnecting a gas hob or cooktop
- Extending or modifying gas pipework
- Commissioning or pressure-testing a gas installation
What About Just Turning Off the Gas?
There is an important distinction here. Operating an existing isolation valve — for example, turning off the valve that's already fitted so you can swap out your hob — is generally something a homeowner can do. But fitting a new valve, replacing an old one, or moving one to a different position on the pipework is restricted work. If you're unsure whether a valve is already present or in good condition, have a licensed gasfitter inspect it before you do anything.
Risks of DIY Gas Work
The consequences of poorly fitted gas components can be severe:
- Gas leaks can lead to explosion or fire
- Carbon monoxide from incomplete combustion is odourless and can be fatal
- Insurance issues — most home and contents policies will not cover damage caused by unlicensed gas work
- Legal liability — you could face fines or prosecution under the Gas Act
- Building consent complications — if you ever sell or renovate, unlicensed work may need to be remediated at your cost
WorkSafe NZ provides guidance on gas safety hazards in the home and workplace.
What a Licensed Gasfitter Will Do
When you hire a licensed gasfitter to fit an isolation valve under your hob, they will typically:
- Isolate the gas supply safely before starting work
- Select the correct valve for your gas type (natural gas or LPG) and pipe size
- Fit and pressure-test the valve to confirm there are no leaks
- Issue a Certificate of Compliance (CoC) — this is a legal document confirming the work meets NZ standards and is required for all restricted gasfitting work
- Reconnect and commission your hob if needed
Always ask your gasfitter for the Certificate of Compliance and keep it with your home records. You'll need it if you sell your property or make an insurance claim.
How to Check Your Gasfitter Is Licensed
Before hiring anyone, verify their licence on the PGDB's online register. A legitimate gasfitter will have a current practising licence and should be happy to show you their licence card. Be wary of anyone who offers to do gas work cheaply without paperwork — it's a red flag.
What Can a Homeowner Do?
As a homeowner, you can legally:
- Operate existing isolation valves (turn them on or off)
- Clean around gas appliances
- Replace a gas hob yourself in some circumstances — but only if a correctly rated isolation valve is already fitted and accessible, and you do not touch the gas pipework or fittings. Even then, check with the PGDB or a gasfitter first, as reconnecting the flexible hose to the valve may still be considered restricted work depending on the fitting type.
When in doubt, don't touch it. The cost of a licensed gasfitter is far less than the cost of a gas-related incident.
Rough Cost Guide
As a general guide only, fitting a single isolation valve is typically a straightforward job for a gasfitter and may take less than an hour. Call two or three local gasfitters for quotes — prices will vary depending on your location, access, and whether additional work is needed.
When to Call a Professional
You should call a licensed gasfitter any time you need to:
- Fit, replace, or relocate a gas isolation valve
- Connect or disconnect a gas hob, oven, or other appliance
- Investigate a suspected gas leak (if you smell gas, leave the building, don't operate switches, and call your gas supplier or 111 immediately)
- Carry out any modification to your gas pipework
You can find qualified, local gasfitters on tradedirectory.co.nz — look for someone with current PGDB registration and good reviews.
Sources & Further Reading
- Plumbers, Gasfitters and Drainlayers Board (PGDB) — licence verification and gas work regulations
- WorkSafe NZ — Gas Safety — hazard information and safety guidance
- MBIE Building Performance — NZ Building Code and compliance information
- BRANZ — building research and best practice guidance
- Energywise — energy efficiency and safe appliance use in NZ homes
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