How Much Does a Plumbing Renovation Cost and What’s Involved?

Where to Start Your Plumbing Renovation

Whether you’re updating a tired laundry or gutting a 1970s bathroom, the process usually starts with a clear plan.

This involves taking stock of what’s in there now and deciding if you need to move the drainage points. All drainage points need to be checked to ensure everything is up to modern Aussie standards.

This is where you’ll need the help of a professional plumber. A qualified plumber will help you get the design right and meet all the compliance requirements. Your plumber will also ensure it all works properly in the long term.

Renovation plans need to include a proper assessment of the whole plumbing system. This will uncover any potential problems and make sure the whole thing runs smoothly.

It’s standard now for homeowners to consider water efficiency and sustainability when planning their renovation.

Renovations often reveal plumbing problems that have been hiding for years. Engaging a qualified plumber means your systems will run smoothly and you will avoid costly mistakes.

Planning Your Plumbing System Layout

First things first, when it comes to any renovation, deciding where everything is going to go. If you’re keeping your toilet, shower and sink in the same locations, your bathroom plumbing costs will stay lower because the main drainage lines won’t need to be moved.

But of course, older homes often have layouts that just don’t make sense for modern living.

Moving a toilet even half a meter can mean cutting into concrete slabs or adjusting the floor joists.

While you’re planning, a licensed plumber will take a look at the condition of your existing pipes. In a lot of older Aussie homes, you might find clay or galvanised steel pipes that are prone to rusting or tree root intrusion.

Swapping these out for modern PVC or copper before you start laying new floor tiles is a whole lot cheaper than doing it later.

When you’re planning, it’s really important to understand and stick to local regulations. Everything will need to meet modern Aussie standards to avoid legal issues or costly rework down the track.

A plumber plays a key role in managing the installation, inspections and communication with all the other trades during this phase.

Good communication and planning among the trades really helps avoid project delays and prevent costly rework jobs.

Getting the planning right and having expert input can make all the difference, improving functionality and creating a space that meets all your needs.

Hiring a Professional

When it comes to a successful renovation project, hiring a professional plumber is probably the most important decision you’ll make.

A qualified plumber brings expertise to every stage of your bathroom renovation. This includes the initial planning of the plumbing system to installing the new fixtures.

By working with a licenced plumber, you can be sure all the plumbing work is done to the highest standard and in full compliance with local building codes.

This doesn’t just help you avoid costly mistakes, it also prevents future plumbing problems that could really disrupt your home and your budget.

Renovating bathrooms can be more than just swapping out old fixtures for new ones. A professional plumber can give you expert advice on the best plumbing solutions for your renovation goals. This includes whether you’re updating a single bathroom or doing a complete home renovation.

Professional plumbers have the experience with renovation plumbing to anticipate any potential problems, recommend quality fixtures and ensure that every aspect of your plumbing meets the current building codes.

The Rough-in Stage

Once you’ve got your layout sorted and the old fixtures are removed, it’s time to start the “rough-in”. This is one of the most important parts of the plumbing renovation process. This is when the plumber installs all the new pipes inside the wall cavities and under the floor. Swapping out old pipes for durable materials at this stage is crucial to prevent leaks, improve water flow and ensure long-lasting performance.

During the rough-in, your plumber will:

• Install new hot and cold water lines
• Make sure the taps and shower heads are at the right height
• Position the drainage for the vanity, bath and toilet
• Install any necessary waterproof components or “puddle flanges” for the floor waste

The rough-in stage can also include checking for backflow prevention checking which is a major focus in the latest Australian standards to protect drinking water.

While they may seem initially more expensive, we highly recommend you only invest in high-quality materials.

Using high-quality materials and sourcing quality products for fittings and pipes is key to long term durability and preventing future plumbing problems.

Future plumbing problems can be incredibly expensive!

Old or outdated pipework hidden behind walls can lead to rust, poor water quality and flow issues. Unseen leaks that come to light during demolition can cause significant rot, mould and structural issues.

Replacing outdated pipes with modern, durable materials prevents future leaks and improve water flow.

Pipe relining can be an alternative for difficult-to-reach pipe areas, costing roughly $400–$1,000 per metre without the need for excavation.

If you’re renovating a kitchen or laundry, this is also when the plumbing for your dishwasher or washing machine is set up. It’s vital to have your appliances chosen by this stage so the plumber knows exactly where the connections need to sit.

Hot Water and Gas Systems – A Home Renovation Must-Have

When it comes to renovating your home, especially if you’re upgrading your kitchen or bathroom, hot water and gas systems are pretty high on the priority list.

Having the right hot water system can boost your comfort levels, cut your energy bills, and even save you quite a bit on your utilities. But that all relies on picking a system that’s just right for your household.

A good plumber will take a look at what you’ve got set up at the moment and recommend the best hot water system for your needs.

If you’re in the process of renovating and are throwing in some new gas appliances such as a new cooktop, oven or even a hot water system, you’re going to want to bring in a licensed plumber to sort the installation out properly.

Gas plumbing’s a bit more complicated than your average plumbing system, and you’ve really got to get it right.

With kitchens and bathrooms, a qualified plumber will sort out your hot water and gas systems so they’re reliable, efficient and ready for the family’s needs.

Understanding Bathroom Plumbing Costs

When you’re working out your budget for renovations, it’s worth thinking about what really drives up the costs.

Some of the key bathroom renovation costs include:

Labour: Labor can be a big factor, especially if you’re in for some serious pipe-chasing through brick walls or navigating tricky sub-floors.

Materials: You’ll want to choose good quality materials and plumbing fixtures that won’t give you any grief in the long run.

Tapware selection: Going for high-end tapware, for instance, might mean more complex in-wall sets for the rough-in compared to your standard taps.

Hot water system upgrades: If you’ve still got an old hot water system that uses low-pressure gravity-fed hot water, you might need to factor in the cost of upgrading. You’ll likely need a mains-pressure tank or a continuous flow gas system to get the most out of that new showerhead you’ve been eyeing.

Unforeseen costs and issues: If any plumbing problems or material shortages crop up, you could end up with project delays, which can play havoc with your timeline and your budget.

Choosing high-quality plumbing fixtures really does give your renovation a lift.

Upgrading to modern plumbing can make a big difference in water flow and help prevent those future leaks.

Preventing Mistakes and Ensuring Compliance

Another large risk in any renovation project is overlooking the smaller details that’ll make sure your plumbing system is safe, efficient and up to code.

A professional plumber will do a thorough inspection of your pipes. This includes identifying any outdated pipes or corroded sections that could cause trouble down the track.

We’ve mentioned this several times, but ensuring your renovation is compliant with local building codes is critical.

Your plumber will know the latest regulations and make sure your whole plumbing system meets or beats them.

That way, you know your renovation is solid, and you can relax knowing you’ve protected your investment.

Testing and Waterproofing

Before you start with the tiling, your plumber should do a pressure test on the lines to make sure there are no tiny leaks that’ll come back to bite you later on.

They should do a final inspection to check the quality and legality of the plumbing job and get that all-important Certification of Compliance or Notification of Completion of Work arranged.

Once they’ve confirmed the pipes are watertight, the area is ready for the waterproofing.

Waterproofing is extremely important. It must be done by a professional so you can be sure it’s done against the building codes.

Waterproofing is like a shield that protects your home’s structure from all that water that’s going to be flowing through the pipes.

For an average-sized bathroom, professional waterproofing (compliant with AS 3740) typically costs between $500 and $900.

If you don’t get the drainage right in your kitchen or bathroom, you could end up with all sorts of problems from slow water flow, stinky smells or blocked pipes.

If water leaks internally and gets into your homes foundations, you could be up for many thousands of dollars to rectify it.

Water Efficiency and Sustainability

More and more renovations these days are about water efficiency and living more sustainably. Not just for the environment, but alsot to save on your utility bills.

A professional plumber can help you choose and install water efficient fixtures such as:

• low flow taps
• dual-flush toilets
• water-saving shower heads

By choosing water-efficient products, you’ll be reducing your household’s water consumption and helping the environment.

The Final Fit-Off

The final bit of the plumbing renovation process is probably the most exciting – the fit-off. This is when your plumber comes back in to connect all the beautiful new fixtures you’ve chosen – the toilets, sinks, taps and shower roses.

Your plumber will make sure drainage is flowing freely and the hot water’s not scalding hot to prevent any accidents.

Once the final checks are all complete , you can show off your new space and start using it.

Your plumber will be there to lend a hand after the job’s done to make sure your new systems keep on running smoothly and efficiently.

Ready to fire up your plumbing renovation project? At DMACK we’re qualified gas plumbers too. Get in touch, and we can come and do a site inspection and give you a quote – job done.

The Ultimate Plumbing Renovation Checklist

Use this checklist to ensure no detail is overlooked during the planning and execution of your project.

Phase 1: Planning & Assessment

[ ] Identify “Behind-the-Wall” Issues: Have a plumber check for outdated clay or galvanised steel pipes before tiling.

[ ] Finalise Layout: Decide if fixtures (toilet, sink, shower) will stay in place or move to save on drainage costs.

[ ] Select Appliances: Choose your dishwasher and washing machine early so the plumber knows exact connection points.

[ ] Check Compliance: Ensure your plan meets modern Australian standards (e.g., AS/NZS 3500).

Phase 2: Rough-In Stage

[ ] Install Water Lines: Set up new hot and cold water lines.

[ ] Position Drainage: Set heights for the vanity, bath, and toilet drainage.

[ ] Pressure Test: Ensure your plumber performs a pressure test on lines to catch leaks before they are sealed in walls.

[ ] Waterproofing Inspection: Verify waterproofing is done to code (AS 3740) before tiling begins.

Phase 3: Final Fit-Off & Certification

[ ] Connect Fixtures: Install and test all taps, toilets, and shower roses.

[ ] Temper Water: Ensure hot water is at a safe temperature to prevent scalding.

[ ] Obtain Certification: Collect your Certificate of Compliance or Notification of Completion.