The cylinder dies once a decade and picks the worst morning.
Hot water is the one plumbing stream where Wellington providers actually publish prices, so use them. A like-for-like 180L replacement has a published package price; a pressure upgrade, a fuel switch or a tight stair-access site pushes it into quote territory. The compliance extras (seismic restraints, safe tray, tempering valve) are not optional, so a quote that skips them is not cheaper, just incomplete.
Is this your stream?
Water around the cylinder, rusty water, a unit past 10 years with recurring faults, or a household that has simply outgrown the tank. Replacement is the job, and published package prices make it comparable.
Cold pipes into the top of the cylinder usually mean an element or thermostat, which is an electrician's job and a much smaller bill. Feel the pipes first; if they are warm or you are not sure, then call the plumber.
What it costs in Wellington
The published package
Plumb Plumbing publishes a like-for-like 180L mains pressure replacement at $3,050–$3,850+GST, a new-position install at $3,150–$3,950+GST, and gas-to-electric conversion at $3,650–$4,450+GST, with a 1-year workmanship guarantee.
The published guide
Ka Pai's replacement cost guide puts most homes at $3,500–$5,500 excl GST for cylinder, materials and install. Easy access lands low; ceiling spaces, cabinetry and Wellington's stair-only sites push it up.
What the cylinder itself costs
Garcia's published breakdown: vented copper 165L $1,200–$1,600, unvented stainless 180L $1,800–$2,300, plus swap-out labour $500–$700, safety devices $300–$500 and disposal $150–$250. NZ-wide budget guides (Unicorns) run $1,800–$3,500 installed.
Wellington providers, compared
Six providers that replace cylinders, grouped by what they are best at. Hover a row for the detail that matters.
Common mistakes
Replacing like-for-like without asking about pressure: many Wellington villas still run low-pressure systems. A failed cylinder is the one natural moment to upgrade to mains pressure, and Maxey specialises in exactly that conversion.
Forgetting the compliance items: a replacement must meet current code. Ka Pai names the list: seismic restraints, safe trays and overflows, and correct tempering valves. If a quote does not mention them, ask.
Calling a plumber for an electrical fault: Ka Pai's own check is to feel the pipes into the top of the cylinder. Cold pipes with no leak usually means an element or thermostat, which is an electrician's job, not a plumber's callout fee.
Repairing a cylinder past its life: Garcia's guidance is that 10+ years old with recurring faults or rising bills means replace, not repair. Sunk repair costs do not extend the cylinder's life.
Ignoring the warranties in the comparison: Plumb Plumbing notes Rheem cylinders carry 5–12 year warranties and Rinnai 5–10 years, and adds its own 1-year workmanship guarantee. Ask for both numbers on every quote.
Attempting any of it yourself: hot water cylinder work is restricted sanitary plumbing. It needs a registered plumber, and an unregistered install can void insurance and warranty.
FAQ
How much does hot water cylinder replacement cost in Wellington?
Two providers publish numbers. Plumb Plumbing charges $3,050–$3,850+GST for a like-for-like 180L mains pressure replacement. Ka Pai's published guide puts most NZ homes at $3,500–$5,500 excl GST including the cylinder, materials and install. NZ-wide guides (Unicorns) run $1,800–$3,500 fully installed at the budget end. Access, position and compliance upgrades decide where you land.
Repair or replace?
A single fault on a cylinder under 10 years old is usually worth repairing. Past 10 years with recurring faults, rising bills or visible leaking, Garcia's published guidance is replace. A leaking cylinder is not a repair candidate at all: turn the water off and treat it as an emergency.
Low pressure or mains pressure: what is the difference?
Older Wellington homes often run low-pressure (header tank or pressure-reducing valve) systems, which is why the shower dribbles when a tap runs. Mains pressure gives a stronger, consistent flow but needs a cylinder and pipework rated for it. Maxey specialises in low-to-mains pressure upgrades.
Gas, electric or heat pump?
Electric cylinders are the default like-for-like swap. Southern installs heat pump water heaters and claims up to 3x the efficiency of a standard electric cylinder, sized for Wellington's climate. Moving between fuels costs more: Plumb Plumbing's published gas-to-electric conversion runs $3,650–$4,450+GST.
No hot water right now: what should I check first?
Feel the pipes running into the top of the cylinder. Cold pipes with nothing leaking points to an electrical fault and an electrician. Warm pipes, water around the cylinder, or a cylinder that has burst is a plumber: turn the water off at the toby and call, because Ka Pai and Harbour City both take emergency hot water calls.
A like-for-like 180L replacement is $3,050–$3,850+GST at Plumb Plumbing's published package price, with Ka Pai's guide at $3,500–$5,500 excl GST once access and compliance are counted. Maxey handles the low-pressure villa upgrade and is the Rheem Service Centre; Southern does heat pump hot water; Garcia shows the cost breakdown; Harbour City and Ka Pai take the emergency calls. Check the pipes before you call, compare warranties, and make sure seismic restraints, safe tray and tempering valve are in the quote.