If you suspect a gas leak in your home, your first priority is always safety — not testing. For a suspected active leak, leave the building immediately, avoid switches and flames, and call your gas retailer or 111. That said, there are some basic checks a homeowner can safely carry out, and understanding what is and isn't legal to do yourself is essential in New Zealand.
Understand What You Can and Cannot Do Legally
In New Zealand, gas work is restricted work under the Gas Act 1992. This means that installing, altering, repairing, or pressure-testing gas pipework must be carried out by a licensed gasfitter registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB). Homeowners are not permitted to perform pressure tests on gas lines or make any modifications to pipework — doing so is illegal and extremely dangerous.
What you can do as a homeowner is carry out a basic visual and smell check to identify obvious warning signs, and use a simple soap solution to check for minor leaks at accessible fittings. These checks do not involve opening, modifying, or pressure-testing any pipework.
Know the Warning Signs of a Gas Leak
Before reaching for any tools, familiarise yourself with the signs that gas may be escaping:
- A smell of rotten eggs or sulphur (the odorant added to natural gas and LPG)
- A hissing or whistling sound near pipes, appliances, or fittings
- Dead or discoloured vegetation in a patch above buried gas lines
- Bubbling in puddles or wet ground near gas lines
- Unexplained higher gas bills suggesting consumption you can't account for
- Pilot lights that keep going out, or appliances that won't stay lit
If you notice any of these signs, treat it as a potential emergency.
What to Do If You Suspect an Active Leak
Safety first: Do not operate any electrical switches, use your phone indoors, light matches, or start a vehicle in an attached garage.
- Turn off the gas at the meter or cylinder valve if it is safe to do so.
- Open windows and doors to ventilate the space.
- Evacuate everyone from the building.
- Call your gas supplier or 111 from outside or a neighbour's property.
- Do not re-enter until a licensed gasfitter or emergency services have declared it safe.
The Soap Solution Check (DIY-Safe for Accessible Fittings)
If you have no signs of an active leak but want to check a visible, accessible fitting — such as the connection at the back of your LPG barbecue or a bayonet fitting — you can use the soap bubble test. This is a widely accepted, simple method:
What you need
- Washing-up liquid mixed with water (roughly 1 part detergent to 3 parts water), or a dedicated leak detection spray available from Bunnings or Mitre 10
- A small brush or cloth
How to do it
- Ensure the gas supply is on (you need pressure in the line to detect a leak).
- Apply the soapy solution generously around the fitting or connection you want to check.
- Watch for bubbles forming — even slow bubbling indicates escaping gas.
- If bubbles appear, turn off the gas immediately and call a licensed gasfitter.
- If no bubbles appear after 30 seconds, the fitting is likely sound at that point.
Important: This test is only suitable for checking external fittings and connections you can see and reach easily. It is not a substitute for a professional pressure test of your entire gas system.
What a Licensed Gasfitter Will Do
A licensed gasfitter has the equipment and authority to carry out a proper pressure test (also called a tightness test) on your gas installation. This involves isolating the system, pressurising it with air or an inert gas, and monitoring for pressure drop over time. This is the only reliable way to confirm your entire gas system is leak-free, and it is required after any new gas work under the NZ Building Code and relevant standards.
Gasfitters must be registered with the PGDB — you can verify a tradesperson's licence on their website before hiring.
Gas Appliance Maintenance Tips
- Have your gas appliances (heaters, hot water systems, cooktops) serviced regularly by a licensed gasfitter — at least every two years is a common recommendation, though check your appliance manufacturer's guidelines.
- Check LPG hoses for cracking, brittleness, or kinking — replace them if damaged.
- Ensure ventilation around gas appliances is never blocked; poor ventilation can cause carbon monoxide build-up, which is odourless and deadly.
- Install a carbon monoxide detector in rooms with gas appliances. These are available from hardware stores and provide an important additional safety layer.
- Rental properties must meet Healthy Homes Standards, which include requirements around heating and ventilation that affect gas appliance use.
When to Call a Professional
Call a licensed gasfitter immediately if:
- You smell gas anywhere in or around your home
- A soap test reveals bubbling at any fitting
- An appliance is behaving unusually (won't light, keeps cutting out, produces yellow or orange flames instead of blue)
- You want a full system pressure test for peace of mind — for example, after buying a home or following a long period of non-use
- Any gas pipework, fittings, or appliances need to be installed, moved, or repaired
You can find qualified, local licensed gasfitters on tradedirectory.co.nz. Always confirm their PGDB registration before work begins.