Can I Do My Own Plumbing in Victoria? A Licensed Plumber’s Guide

Most Melbourne homeowners assume plumbing sits in a grey area — some jobs are fine to DIY, others are “probably best left to a tradie,” and the line between the two is fuzzy. The line is not fuzzy. It’s written down, in Schedule 4 of the Plumbing Regulations 2018 (Victoria), and the work a homeowner can legally do without a licensed plumber is a very short list.

I’m Alister, the licensed plumber and gasfitter behind Prime Plumbing & Gasfitting. BPC Licence No. 103414. This guide walks through what you can legally do yourself in a Victorian home, what crosses into licensed work, and why the distinction matters for your insurance, your home-sale paperwork, and (less dramatically but still real) for you not getting fined.

The legal DIY list, in full

Schedule 4 of the Plumbing Regulations 2018 defines what plumbing work a person without a plumbing licence is allowed to do in Victoria. It’s short. Here it is in plain English:

• Replacing a tap washer or jumper valve. The rubber inside the tap that controls the seal. Tap stops dripping. Genuinely yours to do.
• Replacing a cap, button, or handle on a tap. Cosmetic parts. No water involved.
• Clearing a blockage in a basin, sink, bath, or trough — using a plunger, a hand-held drain auger, or chemical drain cleaner. Not a main drain. Not past the gully trap.
• Cleaning a tap aerator or showerhead outlet. Unscrewing the end fitting, soaking it in vinegar, putting it back.
• Replacing a garden hose tap (the threaded one on the outside wall) if it’s a like-for-like replacement and the existing connection is sound.
• Connecting a flexible garden hose to an existing outdoor fitting.

That’s the entire list. If your job isn’t on it, it’s licensed work — even when a YouTube tutorial makes it look like a 20-minute weekend project.

What counts as licensed plumbing work (where most people get it wrong)

The rule I use with customers: if it stays connected when you walk away, it’s licensed work. Anything that involves a permanent connection to the water supply, the drainage system, or a gas line falls under licensed plumbing or gasfitting. That includes a lot of things people often try themselves:

• Replacing a kitchen or bathroom mixer tap. Cutting flexi hoses to the mains, joining them to the new mixer — that’s pressurised pipework, even if the swap looks “like-for-like.”
• Replacing a toilet. Disconnecting and reconnecting the cistern inlet, the wax seal on the floor pan, the soil pipe. All licensed.
• Replacing a hot water system. Every aspect of hot water work is licensed — storage tank, instantaneous (continuous flow), heat pump, electric, gas. Even a like-for-like replacement in the same spot needs a licensed plumber, a gasfitter if it’s gas, and a Compliance Certificate.
• Replacing a dishwasher tap or fridge water line. The valve that taps into the cold supply behind the cabinet is a permanent connection.
• Any gas appliance work. Connecting a new cooktop, replacing a heater hose, servicing a gas oven, even disconnecting a barbecue from a fixed gas point. Gasfitting is a separate licence (Type A endorsement, regulated by Energy Safe Victoria). If you smell gas or suspect a leak, ring a licensed gasfitter — don’t tape it up yourself.
• Anything behind a tiled wall. Burying pipework you can’t inspect later is licensed work even when it’s “just” extending a cold water line.
• Backflow prevention devices — RPZD, DCV, RPDA. Annual testing is a separate licensed endorsement.
• Thermostatic mixing valves (TMVs). Both installation and annual testing — licensed.

If your job involves cutting into a pressurised pipe, opening up a wall, working on hot water, gas, sewer, or stormwater drainage, or installing any new fixture that ends up plumbed in — it’s licensed work.

Why the law exists — three real consequences

If you do licensed work yourself and nothing immediately goes wrong, you might think “no harm done.” There’s harm done, but it’s invisible until something happens. Three scenarios worth understanding:

1. Home insurance can decline a related claim

Most home insurance policies in Australia have a clause excluding damage from “unauthorised work” or “work performed by an unlicensed tradesperson.” If you replaced the kitchen mixer yourself, the flexi failed six months later, and the under-sink cabinet got soaked — when you lodge the claim, the insurer asks for the Compliance Certificate. You don’t have one. Claim declined. The repair cost (typically $800–$3,000) is yours to wear.

2. At sale settlement, the buyer’s conveyancer can flag it

When you sell your home, the buyer’s conveyancer reviews a Section 32 vendor statement. Recent unlicensed plumbing or gas work — if it’s caught — can hold up settlement or trigger a price renegotiation. Compliance Certificates from BPC (Building & Plumbing Commission, formerly VBA) are the official paper trail buyers’ lawyers expect to see for any work done in the last few years.

3. If unlicensed work causes injury or major damage, it’s a recordable offence

Unlicensed plumbing work is a breach of the Building Act 1993 (Vic). BPC can investigate, and penalties can run to several thousand dollars for individuals. The bigger risk for most homeowners isn’t the fine, though — it’s that a slow leak in the wall causes water damage that ruins $20,000–$50,000 of timber flooring before anyone notices.

Compliance Certificates — what they actually are

Every licensed plumbing or gasfitting job in Victoria ends with a BPC Compliance Certificate. The licensed plumber lodges it electronically with BPC and gives you a copy.

The certificate:

• Lists exactly what work was done
• Names the licensed tradesperson and their licence number
• Confirms the work meets the relevant Australian Standards
• Is the document insurers, conveyancers, rental authorities, and BPC inspectors reference if anything comes up later

For a homeowner, the practical answer is: keep the Compliance Certificate with your property paperwork. If you sell, it’s part of the disclosure pack. If you claim insurance, it’s your proof of compliance.

There’s a small fee built into the certificate (around $20–$30 depending on the work type) that the plumber pays to BPC. It’s not negotiable — every certificate is logged. If a plumber offers to “do the job cash, no paperwork,” they’re offering to do unlicensed work. Politely decline.

Frequently asked questions

Can I install a kitchen mixer tap I bought myself?

No — installing a mixer tap is licensed plumbing work because it involves cutting and joining pressurised water lines. You can absolutely buy the mixer yourself (Bunnings, plumbing supply, online) — we install customer-supplied fittings all the time. Just the installation needs a licensed plumber.

I changed a tap washer myself. Do I need a Compliance Certificate?

No. Washer replacement is one of the items Schedule 4 explicitly permits a homeowner to do without a licence, and it doesn’t require a certificate. Same for clearing a basin or bath blockage with a plunger.

Do I really need a plumber to replace a hot water system?

Yes — by law, every aspect of hot water work is licensed. Removing the old unit, installing the new one, connecting gas or electrical, lodging the Compliance Certificate. Even a like-for-like replacement in the same spot.

What happens if my insurance company finds out I did the plumbing myself?

The most likely outcome is that a claim related to that work gets declined. Less commonly, an insurer might decline to renew the policy. Insurers don’t door-knock to check — they ask for the Compliance Certificate when you claim, and if you can’t produce one for licensed work, the claim is denied.

How much does a Compliance Certificate cost?

The certificate itself isn’t usually a separate line item — it’s built into the job cost. The plumber pays a small lodgement fee to BPC (about $20–$30 per certificate) and that’s part of what the labour quote covers. If a plumber’s quote is conspicuously cheap, sometimes it’s because they’re skipping the certificate.

My neighbour did his own toilet install and it’s been fine for years. Is the law actually enforced?

It’s enforced reactively, not proactively. BPC isn’t door-knocking. The law comes up when something goes wrong — an insurance claim, a sale settlement, a neighbour dispute about a shared wall, a renter raising a maintenance issue. The toilet that’s “been fine for years” usually fails at the wax seal or the inlet flexi between year 5 and year 10, and the damage often costs more than the original licensed install would have.

What about a leaking outdoor tap — that’s on the DIY list, right?

Like-for-like replacement of an existing garden tap is on the Schedule 4 DIY list. But if the existing connection is damaged or corroded, or if you need to cut into the wall pipe to reach the connection, that part of the job is licensed work. Use the rule of thumb: if you can unscrew the old tap and screw the new one straight onto the existing thread, you’re fine. If you need any pipe cutting or wall opening, call a plumber.

If you’re not sure, ring

The simplest rule: if you’re unsure whether your job is DIY or licensed, ring 0475 407 670 or contact Prime Plumbing & Gasfitting. I’ll tell you over the phone, no obligation. If it’s a tap washer or a hose tap, I’ll save you the call-out and tell you to do it yourself. If it’s a mixer, a hot water unit, or anything past the meter — we’ll book it in, and you’ll get the Compliance Certificate when we’re finished.

Licensed plumbers exist for the same reason licensed electricians exist: water and gas behind walls is just as risky as electricity behind walls, and the cost of getting it wrong is rarely visible until it’s already expensive.

— Alister Williams, Prime Plumbing & Gasfitting
BPC Licence No. 103414 · ABN 12 721 359 467 · Serving Melbourne since 2014

Related reading

• Annual plumbing maintenance checklist for Melbourne homes
• Are your flexible hoses a ticking time bomb? A Melbourne plumber’s guide
• Hot water system maintenance tips to avoid emergencies