When it's an installation, not a straight swap
- You're building a new home or a granny flat.
- A renovation adds a bathroom, or moves one.
- The unit has to move: out of a cupboard, off a wall, or closer to where the hot water is used.
- You want a second system for a far end of the house.
- You're changing fuel and the new unit needs a different spot.
New homes and the gas question
Victoria. The Government has said that from 1 January 2027, "all new homes will be built all electric". If you're building, plan an electric system from the first drawings, and check current rules with your builder.
ACT. New gas network connections have been blocked since 8 December 2023 in residential zones, so a new home there won't get one.
Queensland. For new dwellings, the hot water system's energy performance counts towards the National Construction Code's Whole of Home energy budget.
NSW. A new home needs a BASIX certificate. Ask your builder how your hot water choice fits into it.
What a plumber will do on an install
Pick the spot
A plumber will check clearances and service access, plus either the flue path for gas or the airflow a heat pump needs.
Run the pipes
Hot and cold lines go to the new position. A long hot run means a wait at the tap, so a spot near the bathrooms often makes sense.
Connect the energy
A gas line is extended and pressure tested, or a suitable power supply is arranged with an electrician.
Fit the valves
An isolating valve, a relief valve with its drain line taken somewhere safe, and temperature control where your state requires it.
Commission and hand over
Fill it, bleed the air, fire it up and check the temperatures. Then you get the manuals and the paperwork.
Moving an existing system
Relocating a unit means new pipework, not just a new spot for the tank. In Western Australia, a restricted plumbing permit covers water heater replacement only where no pipe changes are needed, so a move is work for a licensed plumber rather than a permit holder.
WA's temperature rule also reaches relocations: a temperature control device is required when a heater is moved as well as when it's replaced, with an exception for basins. Other states are on our tempering valves page.
Paperwork before and after
In Western Australia, installing a water heater is major work. The contractor gives a notice of intention at least 24 hours before starting, and must give you a certificate of compliance within five working days of finishing.
In South Australia, water heater installation is on the list of work that needs an electronic certificate of compliance.
In Queensland, solar and heat pump systems must be installed by a hot water installer holding a QBCC solar and heat pump endorsement.
In Victoria, only a licensed plumber can issue a compliance certificate. See our compliance certificate guide for more.
Your part and the plumber's
You can
- Tell the builder or plumber how many people will live there.
- Say where you'd like the unit, and ask the plumber to confirm it works.
- Keep the chosen spot clear for access and airflow.
- Ask your electrician early about the circuit for an electric or heat pump unit.
Leave to a licensed plumber
- Pipework, valves and the relief valve drain.
- Gas connections and flues.
- Temperature control devices.
- Notices and certificates.
Questions for the installer
- Why this spot, and how far is it from the main bathroom?
- Will the system need a tempering valve here?
- Who handles the electrical side?
- What notices or certificates will you lodge, and when do I get a copy?
- For a heat pump or solar, is the model on the register for STCs?
What we would do
Bring a hot water specialist in early, before the slab and frame decide where pipes can run. Moving a unit after the walls are lined costs time and work you could have avoided. Ask them to place it close to the bathrooms with room to service it, and to tell you up front which notices and certificates your state expects.