Permits, certificates and the paperwork that matters.
Good news first: you do not need a City of Casey permit to replace a hot water system. What you do need is a plumbing compliance certificate lodged with the Victorian Building Authority - and that single document is what protects you at sale, at claim time, and every time someone touches the gas line for the next twenty years.
Council has nothing to do with your hot water system.
This surprises people who have just been through a deck or a carport with the City of Casey, because those genuinely do involve permits, setbacks and a waiting period. Hot water is different. Replacing a unit in the same position is exempt from building permits under the Building Regulations 2018. There is nothing to lodge with council, no fee, no wait, and no inspection to book. Same story in Cardinia Shire for Officer and Beaconsfield, and in Greater Dandenong - it is state regulation, not a local rule.
Relocating the unit is the one people ask about next. Moving a tank from an internal laundry cupboard to an external wall, or repositioning a heat-pump compressor away from a bedroom window, still does not normally require a building permit. What it requires is a registered plumber signing off that the new position satisfies AS 3500.4 clearance and venting requirements - and for a gas unit, the flue clearances in AS/NZS 5601.1, which are the reason you cannot simply tuck a gas unit under a low eave or next to an opening window.
So the entire regulatory burden of a hot water replacement in South East Melbourne comes down to one document, produced by the person doing the work. Which makes it worth understanding what that document actually is.
What a compliance certificate is, and why it is the whole game.
A plumbing compliance certificate is the licensed plumber's formal statement that the work complies with the regulations and the relevant standards. It is lodged with the Victorian Building Authority, not with council. Under the Plumbing Regulations 2018 it is required for plumbing work valued over $750 - and every hot water replacement in this market clears that bar comfortably, so in practice it is required on all of them.
Three reasons it matters far beyond the day of the job:
- At sale. A purchaser's conveyancer who notices the unit is newer than the house will ask who did it. No certificate means undocumented plumbing work on your property, and that is a conversation you do not want during a settlement.
- At claim time. When a tank lets go and floods a hallway, the assessor asks who installed it and whether it was compliant. Policies exclude loss arising from work that was required to be licensed and was not. The certificate is your evidence. Detail on our burst hot water insurance page.
- At the next gas job. Any future gasfitter working on the property is reading the history of what was done. Gaps in that history slow everything down and cost you money.
If a quote for a hot water replacement makes no mention of a compliance certificate, that is not an oversight. It is information.
The four documents your plumber is actually working to.
- AS/NZS 3500.4 - Heated water services. The main one. Storage at 60 degrees or above to suppress Legionella; delivery to bathroom outlets at no more than 50 degrees, and 45 degrees in aged-care, early-childhood and healthcare settings; relief valve drainage; sizing for peak demand. The tempering valve exists because of this standard.
- AS/NZS 3500.1 - Water services. The cold side feeding the unit, isolation and backflow.
- AS/NZS 5601.1 - Gas installations. Gas connection, pressure testing and flue clearances. Type A gasfitter work only, under Energy Safe Victoria.
- AS/NZS 4234 - Heated water systems energy calculation. The one that decides how many STCs a heat-pump or solar system is worth, which is money in your pocket.
Above all of them sits the Plumbing Code of Australia, which is NCC Volume Three, and which references the AS 3500 series for hot water. Appliance safety adds AS/NZS 60335.2.21 for storage water heaters and AS/NZS 60335.2.40 for heat-pumps. You do not need to read any of these. You do need your plumber to have. The trades we coordinate with and the reference links are on our local trades page.
What the Gas Substitution Roadmap means for your next unit.
You can still replace gas with gas in an existing South East Melbourne home today. That is the honest current position and we will not pretend otherwise to sell you a heat-pump. But the direction is not ambiguous. Victoria's Gas Substitution Roadmap has progressively removed gas from new builds requiring a planning permit, and from 1 March 2027 a gas hot water system in a rental property that reaches end of life is to be replaced with an efficient electric system. Those dates have moved before, so we confirm the current rules at quote time rather than repeating last year's version. If you own a rental, that rule lands on top of your existing urgent-repair obligations, which is a different clock again.
The practical read for a homeowner in 2026: if your gas unit dies this year, a like-for-like gas replacement at $1,800 to $2,800 is legal, fast and cheap. It is also probably the last gas hot water system that house will ever have, and it locks in gas standing charges for another decade. A heat-pump at $4,000 to $5,500 installed, less roughly $700 to $1,100 of STCs and the $1,000 Solar Victoria rebate for eligible owner-occupiers, lands in the same neighbourhood on net cost and runs at roughly a third of the price. That is a decision, not a formality - see the gas hot water page for the case each way.
A worked example - Endeavour Hills, gas storage to heat-pump.
170L external gas storage, 2008 plate, cylinder weeping. Owner-occupier, eligible for the Solar Victoria rebate. Two quotes: like-for-like 5-star gas storage at $2,150 including the gas compliance certificate and disposal, done in an afternoon; or a 280L Reclaim heat-pump at $4,700 installed, less $900 STCs and $1,000 Solar Vic, landing at $2,800 net, with an electrician running a dedicated circuit the day before.
Paperwork on the heat-pump path: one plumbing compliance certificate for the new heated water service, one gas decommissioning record because the gas line is capped, and one electrical certificate of compliance for the new circuit. Three documents instead of one, all of which we email to the owner within five business days. Net extra cost over the gas option: $650. Running cost saving: roughly $500 a year. No permit required from the City of Casey for either path.
Permit and paperwork questions.
Do I need a council permit to replace a hot water system in South East Melbourne?
No. Replacing a hot water unit in the same position is exempt from building permits under the Building Regulations 2018, so the City of Casey has no part to play and there is nothing to lodge with council. What is required is a plumbing compliance certificate from the licensed plumber, lodged with the Victorian Building Authority. Relocating the unit or a heat-pump compressor to a new position does not usually need a permit either, but it does need a registered plumber to confirm the new location meets AS 3500.4 clearance and venting requirements.
What is a plumbing compliance certificate and when must I get one?
It is the licensed plumber's formal statement that the work complies with the regulations and the relevant standards, and it is lodged with the Victorian Building Authority. Under the Plumbing Regulations 2018 it is required for plumbing work valued over $750, which every hot water replacement in South East Melbourne exceeds. It carries a warranty period on the plumbing work behind it. You should receive a copy - if a plumber quotes a hot water replacement and does not mention a certificate, that is your signal to stop and ask why.
What paperwork do I get when a gas hot water unit is removed?
Two documents rather than one. You get the plumbing compliance certificate for the new heated water service, and you get a separate record for the gas decommissioning, which Energy Safe Victoria requires whenever a gas line is capped. Keep both. The decommissioning record matters more than people expect: it is what a future gasfitter, a purchaser's conveyancer, or an insurance assessor looks for when they find a capped gas point behind the house and want to know that it was capped properly rather than by someone's brother-in-law.
Which standards actually apply to a hot water install in Victoria?
Four do most of the work. AS/NZS 3500.4 governs heated water services: storage at 60 degrees or above for Legionella control, delivery to bathroom outlets at no more than 50 degrees, and relief valve drainage. AS/NZS 3500.1 covers the cold water side. AS/NZS 5601.1 governs gas installations, including flue clearances. AS/NZS 4234 sets the energy calculation that determines a heat-pump or solar system's STC value. Above them all sits the Plumbing Code of Australia, which is NCC Volume Three. Your plumber works to these whether you have heard of them or not.
Is a gas hot water replacement still allowed in Victoria in 2026?
For an existing home, yes - you can still replace gas with gas today. The direction of travel is clear though. Victoria's Gas Substitution Roadmap has progressively removed gas from new builds requiring a planning permit, and from 1 March 2027 a gas hot water system in a rental property that reaches end of life is to be replaced with an efficient electric system. These dates have shifted before, so we confirm the current position at quote time rather than repeating what was true last year. If you are buying a gas unit in 2026, buy it knowing it may be the last one.
Certified hot water across the City of Casey and the South East.
Certificate lodged, copy emailed, no chasing.
VBA-licensed plumber and Type A gasfitter on every job. Ranges on the pricing guide.