Your LPG cylinder's expiry (retest) date is stamped directly onto the metal collar or valve guard at the top of the cylinder — no app or special tool needed. In New Zealand, cylinders must be periodically retested under the Health and Safety at Work (Hazardous Substances) Regulations 2017, and using an out-of-date cylinder is both illegal and potentially dangerous.
Where to Find the Date Stamp
Look at the steel collar (the ring of metal around the valve at the top of the cylinder). You'll see a series of letters and numbers stamped or embossed into the metal. The key marking to find is the test date, which is typically shown as a month and year — for example, "09 26" means September 2026.
You may also see:
- The original manufacture date (often shown as a four-digit year or month/year)
- A retest date added after the cylinder was last inspected (sometimes shown with an inspector's mark or stamp alongside it)
- The cylinder's tare weight (empty weight in kilograms) and water capacity
If the stamping is hard to read due to rust or paint, gently clean the collar with a dry cloth. Do not use water or solvents near the valve.
How Long Are NZ LPG Cylinders Valid?
Under NZ regulations, standard LPG cylinders (such as the common 9 kg and 45 kg sizes used for BBQs, heating, and cooking) must be retested every 10 years. The clock starts from the date of manufacture, and after each successful retest, a new date is stamped showing when the next retest is due.
Here's a quick summary:
| Cylinder type | Retest interval |
|---|---|
| Standard steel LPG cylinders (e.g. 9 kg, 45 kg) | Every 10 years |
| Composite/fibreglass cylinders | Check manufacturer specs — often shorter |
| Cylinders past retest date | Must NOT be refilled or used |
If your cylinder is past its retest date, your gas retailer or refiller is legally required to refuse to refill it. This is a safety measure, not just a technicality.
What Happens at a Retest?
Retesting must be carried out by an approved cylinder testing facility — this is not a DIY job. The tester will:
- Inspect the cylinder externally for corrosion, dents, and damage
- Conduct a hydrostatic pressure test (filling the cylinder with water under high pressure to check for leaks or weakness)
- Inspect the valve and fittings
- Stamp a new retest date if the cylinder passes
If the cylinder fails, it will be condemned and decommissioned — it cannot be repaired and put back into service.
How to Check if Your Cylinder Is Safe to Use Right Now
Before connecting or using any LPG cylinder, do a quick visual check:
- Read the collar stamp — confirm the retest date hasn't passed
- Check for rust or corrosion, especially around the base and seams
- Look for dents, bulges, or gouges in the cylinder body
- Inspect the valve — it should turn smoothly and show no signs of damage or leaking
- Smell for gas — if you detect an LPG smell (similar to rotten cabbage or mercaptan), do not use the cylinder
If anything looks wrong, do not use the cylinder. Contact your LPG supplier or a licensed gasfitter.
Storing and Handling LPG Cylinders Safely
- Always store cylinders upright and outdoors or in a well-ventilated area
- Keep away from heat sources, ignition points, and direct sunlight
- Never store cylinders inside your home, garage, or enclosed space
- Transport cylinders upright and secured in your vehicle — never in the boot of a sealed car
For detailed safe handling guidance, WorkSafe NZ publishes information on hazardous substances including LPG.
Swapping vs. Refilling Your Cylinder
Many NZ homeowners use swap-and-go services (available at service stations and hardware stores) rather than getting cylinders refilled. With a swap, the retailer takes your old cylinder and gives you a tested, full one — so you don't need to worry about the retest date yourself, as the retailer manages that.
If you prefer to own and refill your cylinder, you are responsible for keeping track of the retest date and getting it retested before it expires.
When to Call a Professional
While reading the date stamp is something any homeowner can do, the following tasks are restricted work under NZ law and must only be carried out by a licensed gasfitter registered with the Plumbers, Gasfitters and Drainlayers Board (PGDB):
- Replacing or repairing cylinder valves
- Connecting or modifying gas appliances and pipework
- Any work on your home's gas installation
Cylinder retesting and condemnation must also be done by an approved testing facility — not a DIY task.
If you're unsure about the condition of your cylinder, your gas connections, or your appliances, it's always worth getting a licensed gasfitter to take a look. You can find qualified local gasfitters on tradedirectory.co.nz.