What Plumbing Can I Do Myself in Victoria?

Most people assume plumbing sits in a grey area, where some jobs are fine to have a go at and others are best left alone, and the line between them is fuzzy. The line is not fuzzy. It is written down in Schedule 4 of the Plumbing Regulations 2018 (Victoria), and it is short enough to read in a minute.

I’m Alister, the licensed plumber and gasfitter behind Prime Plumbing & Gasfitting. BPC Licence No. 103414. Plenty of plumbers would rather you didn’t know which jobs you can do without them. I’d rather tell you, because the ones you can do are the cheap ones, and I’d sooner you rang me for the jobs that actually need a licence.

The six jobs you can legally do yourself

This is the complete list for a homeowner without a plumbing licence in Victoria:

• Replacing a tap washer or jumper valve. The rubber disc inside the tap that makes the seal. This is what stops a dripping tap. 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. Unscrew the end fitting, soak it in vinegar, put it back.
• Replacing a garden hose tap (the threaded one on the outside wall) if it is a like-for-like swap and the existing connection is sound.
• Connecting a flexible garden hose to an existing outdoor fitting.

That is the entire list. If your job is not on it, it is licensed work, even when a video makes it look like a twenty minute job.

How to do the three you’ll actually need

Four of the six are self-explanatory. These are the three worth walking through, because they are the ones people ring about and then feel silly when I tell them to do it themselves.

Replacing a tap washer (the fix for a dripping tap)

A dripping tap is almost always a perished washer. You’ll need a shifting spanner, a flat screwdriver, a cloth, and a washer or jumper valve to suit. Take the old one to the hardware shop rather than guessing the size.

1. Turn the water off. Under a sink there is usually an isolation valve on the pipe. If there isn’t one, use the main stop tap, normally out the front near the meter.
2. Open the tap fully and let it drain. That releases the pressure still sitting in the line.
3. Prise off the coloured hot or cold button on top of the handle. There is a screw underneath. Undo it and lift the handle off.
4. Wrap the cloth around the chrome cover so the spanner doesn’t chew it up, then undo the bonnet underneath and lift the spindle out.
5. The jumper valve sits in the body of the tap with the washer on its base. Undo the small nut and swap the washer, or just replace the whole jumper valve. Replacing the lot is easier and costs a couple of dollars more.
6. Put it back together in reverse, then turn the water on slowly and run the tap.

If it still drips after a new washer, stop there. It means the brass seat inside the tap is scored, and re-seating it needs a tool and a licence. That’s the point where it becomes my job.

Clearing a blocked basin, sink or bath

Only for the fixture itself. A blockage in the pipework past the gully trap is licensed work, and it is also a different job requiring different gear.

1. Bail out most of the standing water, leaving just enough to cover the plunger cup.
2. Hold a wet cloth firmly over the overflow hole. Skip this and the plunger pushes air straight out of the overflow instead of into the blockage, which is why plunging often seems to do nothing.
3. Plunge with steady strokes for fifteen to twenty seconds, then lift and check whether it drains.
4. If plunging won’t shift it, feed a hand-held drain auger down the waste and wind it through.

Two warnings worth having. Do not plunge after pouring in chemical drain cleaner, because it can splash back. And if the blockage keeps returning, or more than one fixture is draining slowly at the same time, the problem is in the main drain rather than under the basin. That is licensed work, and usually a tree root or a broken pipe rather than anything you did.

Replacing an outdoor garden tap

Legal only when it is a straight like-for-like swap onto a sound existing thread.

1. Turn the water off at the main stop tap and open the garden tap to drain the line.
2. Unscrew the old tap anticlockwise with the shifting spanner.
3. Clean the exposed thread with a rag so the new tap seats properly.
4. Wrap plumber’s thread tape around the new tap’s thread, four or five turns, in the direction the tap will screw on.
5. Screw it on by hand, then nip it up with the spanner, finishing with the outlet pointing down.
6. Turn the water back on and watch the joint for a minute.

If the thread coming out of the wall is corroded, or the whole pipe turns when you unscrew the tap, stop. Turning the pipe can crack the fitting inside the wall, and then a ten dollar tap becomes a wall repair.

Where the line is: what needs a licensed plumber

The rule I use with customers: if it stays connected when you walk away, it is licensed work. Anything permanently joined to the water supply, the drainage system, or a gas line falls under licensed plumbing or gasfitting. That includes a lot of jobs people attempt:

• Replacing a kitchen or bathroom mixer tap. Cutting flexi hoses into the mains and joining them to the new mixer is pressurised pipework, even when the swap looks like-for-like.
• Replacing a toilet. The cistern inlet, the seal on the floor pan, the soil pipe. All licensed.
• Replacing a hot water system. Every aspect of hot water work is licensed: storage, continuous flow, heat pump, electric, gas. Even a like-for-like swap in the same spot needs a licensed plumber, a gasfitter if it runs on 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 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, ring a licensed gasfitter. Do not tape it up.
• Anything behind a tiled wall. Burying pipework you cannot inspect later is licensed work, even when it is only extending a cold water line.
• Backflow prevention devices, RPZD, DCV, RPDA. Annual testing is a separate licensed endorsement.
• Thermostatic mixing valves (TMVs). Installation and annual testing, both licensed.

If the job means cutting into a pressurised pipe, opening a wall, touching hot water, gas, sewer or stormwater, or installing a fixture that ends up plumbed in, it is licensed work.

Why the law exists, three real consequences

If you do licensed work yourself and nothing goes wrong straight away, it is easy to assume no harm was done. The harm is usually there, just invisible until something happens.

1. Home insurance can decline a related claim

Most Australian home policies exclude damage from unauthorised work, or work performed by an unlicensed tradesperson. Say you fitted the kitchen mixer yourself, the flexi hose failed six months later, and the cabinet underneath got soaked. When you lodge the claim, the insurer asks for the Compliance Certificate. You haven’t got one. Claim declined, and the repair, typically $800 to $3,000, is yours to wear.

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

When you sell, the buyer’s conveyancer reviews the Section 32 vendor statement. Recent unlicensed plumbing or gas work, if caught, can hold up settlement or trigger a price renegotiation. Compliance Certificates from BPC (Building & Plumbing Commission, formerly VBA) are the paper trail buyers’ lawyers expect for any recent work.

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

Unlicensed plumbing work breaches the Building Act 1993 (Vic). BPC can investigate, and penalties run to several thousand dollars for individuals. For most homeowners the fine is not the real risk. The real risk is a slow leak inside a wall quietly ruining $20,000 to $50,000 of flooring before anybody notices.

Compliance Certificates, what they actually are

Every licensed plumbing or gasfitting job in Victoria ends with a BPC Compliance Certificate. The plumber lodges it electronically 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 what insurers, conveyancers, rental authorities and BPC inspectors reference if anything comes up later

For a homeowner the practical advice is simple: keep the Compliance Certificate with your property paperwork. If you sell, it goes in the disclosure pack. If you claim on insurance, it is your proof.

There is a small lodgement fee built into it, roughly $20 to $30 depending on the work type, which the plumber pays to BPC. It is not negotiable and every certificate is logged. If someone offers to do the job cash with no paperwork, they are 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 means cutting and joining pressurised water lines. You can absolutely buy the mixer yourself, from Bunnings, a plumbing supplier or online. We install customer-supplied fittings all the time. It is only the installation that needs a licence.

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

No. Washer replacement is one of the items Schedule 4 explicitly permits without a licence, and it needs no 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, and 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 likely outcome is that a claim related to that work gets declined. Less commonly an insurer might decline to renew. Insurers don’t door-knock to check. They ask for the Compliance Certificate when you claim, and if you cannot produce one for licensed work, the claim is denied.

How much does a Compliance Certificate cost?

It is not usually a separate line item, it is built into the job cost. The plumber pays a lodgement fee to BPC, roughly $20 to $30 per certificate, and that sits inside the labour quote. If a quote looks unusually cheap, sometimes it is because the certificate is being skipped.

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

It is enforced reactively rather than proactively. BPC is not door-knocking. The law surfaces when something goes wrong: an insurance claim, a sale settlement, a dispute about a shared wall, a renter raising a maintenance issue. The toilet that has been fine for years usually fails at the pan seal or the inlet flexi somewhere between year five and year ten, and the damage often costs more than the 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 list. But if the existing connection is damaged or corroded, or you need to cut into the wall pipe to reach it, that part is licensed work. 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 it needs pipe cutting or opening a wall, ring a plumber.

If you’re not sure, ring

The simplest rule: if you are 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 is a tap washer or a hose tap, I’ll save you the call-out and tell you to do it yourself. If it is 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 do. Water and gas behind a wall carry the same kind of risk as electricity behind a wall, and the cost of getting it wrong is rarely visible until it is 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