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Understanding replumbing costs in Australia

What replumbing a house costs in 2026

Replumbing a house in Australia in 2026 typically costs $6,000 to $25,000 depending on size, scope and access. A two bedroom unit or small home replumbed for hot and cold supply only runs $5,000 to $9,000. The common case, a three bedroom single storey house with accessible subfloor and roof space, lands at $8,000 to $15,000. A four bedroom two bathroom home is $12,000 to $20,000, and large or two storey homes, or jobs including drainage and sewer, reach $20,000 to $35,000. Expressed per fixture, plumbers often work on $600 to $1,200 per fixture point for supply, which is a useful sanity check on a quote.

Why houses get replumbed

There are three main triggers. Galvanised steel pipe, standard in Australian homes built before the 1970s, corrodes internally and progressively chokes flow, which shows up as rusty water, poor pressure and repeated pinhole leaks. Early plastic systems from certain eras have known failure modes and can fail suddenly. And copper, while long lived, eventually develops pinholes in aggressive water or where it was installed with poor workmanship or in contact with dissimilar metals. The signal that it is time to replumb rather than repair is repetition. One leak is a repair. Three leaks in two years in different places means the system is at end of life and each repair is buying a few months.

Scope decisions that move the price

Supply only, meaning hot and cold water pipework from the meter and hot water service to every fixture, is the base scope and the most common. Adding internal drainage, which is the waste pipework from sinks, basins, showers and toilets, increases the cost by roughly 40 per cent because drainage runs are larger, must maintain fall and are more often buried in floors. A full replumb including the sewer connection and stormwater is the largest scope and typically involves excavation in the yard. Most houses do not need drainage replaced at the same time as supply, so ask the plumber to justify it with a camera inspection rather than including it by default.

Slab homes and rerouting overhead

Access is the single biggest cost variable. In a home with a subfloor and an accessible roof space, new pipework can be run without opening much at all, and the job is comparatively clean. In a slab on ground home, pipes cast into or beneath the concrete cannot be economically replaced in place. The standard solution is to abandon the in-slab runs entirely and reroute new pipework overhead through the roof space and down internal wall cavities to each fixture. This is usually cheaper and far less destructive than cutting the slab, but it means wall penetrations at every drop, which have to be patched, plastered and painted afterwards.

Making good is the forgotten line item

Plumbers cut access holes in walls and ceilings and, in most cases, do not repair them. On a whole house replumb that reinstatement, meaning patching, plastering, sanding and painting, can be $2,000 to $6,000 and occasionally more if tiles have to be removed and replaced in wet areas. This is the most commonly omitted item in a replumbing quote and the most common source of a nasty surprise. Ask every quote to state explicitly whether making good is included, excluded or provisional, because two quotes $5,000 apart frequently differ on exactly this and nothing else.

Licensing, compliance and insurance

Plumbing and drainage work is licensed in every Australian state and territory, and there is no owner builder exemption for the work itself in most jurisdictions. A licensed plumber must issue a certificate of compliance for the completed work, and depending on the state and scope, the work may be subject to inspection by the plumbing regulator or water authority. Keep the certificate, since it matters at sale, at insurance claim time, and for any warranty on the work. Unlicensed plumbing can void home insurance entirely, which turns a saving of a few thousand dollars into an uninsured house.

Materials and how to compare quotes

Most modern replumbing in Australia uses either copper or cross linked polyethylene, commonly known as PEX. Copper is durable, proven and more expensive in labour because every joint is soldered or crimped. PEX is faster to install, flexible enough to be pulled through cavities with fewer joints, and cheaper, and quality PEX systems carry long warranties. Some owners prefer copper on principle and some plumbers strongly prefer PEX for retrofit work because it reduces the number of wall openings needed. When comparing quotes, check the pipe material and brand, the number of fixture points included, whether tapware and fixtures are supplied or by others, whether making good is included, what the warranty covers, and whether the hot water service replacement is in or out.