Picture this. You wake up, jump in the shower, and the water’s barely warm. You walk into the laundry and spot a damp patch near your old hot water cylinder. Great. Another morning gone sideways. Then the question hits — who do I even call for this? A plumber? Or maybe an electrician? It’s not exactly clear, right? And if you call the wrong one first, you’ll waste time, money, and maybe a few more cold showers than you’d like.
At HandyHub NZ, we talk to homeowners in this exact situation every week. So don’t stress. Let’s go over it in plain language — no jargon, no confusion — just the truth about who handles what, and how to get your hot water sorted safely and properly.
Most of the time, you’ll start with a registered plumber. They’re the ones who deal with all the pipework, water flow, valves, and drainage. But here’s the kicker — you’ll often need an electrician too, especially if there’s any power wiring involved.
So, think of it like this. The plumber handles everything that carries water. The electrician makes sure the unit actually heats it up. Depending on your setup, they might even work together on the same job.
It’s a bit like getting a car serviced — your mechanic fixes the engine, but if there’s an electrical fault, they’ll call the auto sparky. Same deal here.
What Plumbers Do
Your plumber is the backbone of the whole job. They’ll:
They’re the ones who make sure everything actually flows and that your cylinder won’t leak or burst down the line.
What Electricians Do
The electrician’s role is about keeping things safe and powered. They’ll:
Both are essential. One keeps the water flowing, the other keeps it warm and safe.
Not every Auckland home has the same setup. Let’s run through the main systems so you know what applies to yours.
This is what most Auckland homes still use. In a straightforward replacement, you’ll only need a plumber. They’ll handle everything — disconnect, replace, reconnect.
But if the wiring needs adjusting, like if the cylinder’s moved or upgraded, then you’ll also need an electrician to connect it safely. Most good plumbers already have a sparky they trust and can bring them in, so you don’t have to chase two people.
In other words, call the plumber first, and they’ll handle the rest.
Here’s where it gets a little trickier. Gas systems need a certified gasfitter, which is usually a registered plumber with a gas license. They’ll sort out the gas lines, flue, and water connections.
But you’ll still need an electrician to connect the ignition, controls, or power outlet. It’s basically teamwork — the plumber-gasfitter deals with gas and water, the electrician makes it light up.
So for gas units, expect both.
These are a bit of a mix of plumbing, power, and cooling tech. You’ll need:
It’s definitely not a one-person job. If someone says they can do it all alone, that’s your first red flag.
Now, here’s the part a lot of people don’t realise. In New Zealand, it’s illegal for unlicensed people to install or alter hot water systems. That means no handyman, no mate down the road, and no “cash job” from someone who “used to be a plumber back in the day.”
All hot water work — whether it’s plumbing, gas, or electrical — must be done by registered professionals. That’s set by the Plumbers, Gasfitters, and Drainlayers Board (PGDB) and the Electrical Workers Registration Board.
If someone touches your system without being licensed, your insurance can refuse claims if anything goes wrong. Even worse, you could be putting your family at risk — from leaks, electric shocks, or gas faults.
A proper plumber and electrician will always issue Certificates of Compliance once the job’s done. Keep those — they’re your proof that everything’s up to NZ standards and safe for resale or insurance.
So yeah, maybe skip the “mate’s rates” offer this time.
Here’s how to make it stress-free:
Follow that list, and you won’t have to stress about who does what or whether it’s legal.
So, plumber or electrician for your hot water heater? The short version — you’ll nearly always start with a plumber. They’ll take care of the whole thing and bring in the right people if the job needs extra work.
At HandyHub NZ, we keep it simple for Auckland homeowners. We only work with fully registered, insured plumbers and electricians who know the local rules inside out. Whether it’s a quick replacement, a full upgrade, or a switch to gas, we’ll connect you with the right pro — fast and fuss-free.
No cold showers, no dodgy workmanship, just honest Kiwi tradespeople who know their stuff.