A kitchen renovation is a big investment—and one of the best ways to modernise your home and make it more functional. But while things like new benchtops and splashbacks get all the attention, I’ve seen firsthand how poor planning around plumbing can lead to costly mistakes that derail the whole project.
I’m Will from Flowtec Plumbing and Gas, and I’ve worked on more kitchen renos than I can count. The good news? Most plumbing issues are completely avoidable with the right advice and a bit of forward thinking. So here are a few of the most common mistakes I see—and how you can steer clear of them.
1. Moving sinks or dishwashers without a plan
Why it causes issues:
Relocating a sink, dishwasher, or gas cooktop might seem like a simple design choice—but every move means more pipework, drainage, or gas lines to relocate. That adds time, cost, and the potential for problems if it’s not done properly.
My advice:
- Stick to the existing layout if you can—it’ll save you money and hassle.
- Get a plumber involved early. Before you start moving cabinets around, I can come out and assess what’s possible.
- Plan for access. Make sure we’ve got enough space to get to valves and pipework later—your future self will thank you.
2. Choosing the wrong sink or tap
What can go wrong:
Not all taps and sinks suit all plumbing systems. Choosing one that’s not compatible can cause weak water pressure, leaks—or even noisy pipes (we’ve all heard that annoying banging).
What to do instead:
- Match your tap to your home’s water pressure.
- Some styles need special fittings—check with your plumber before buying.
- Go for quality. Cheaper taps can cost you more in the long run with leaks or corrosion.
3. Ignoring shut-off valves
Why it matters:
I always recommend installing shut-off valves for sinks, dishwashers, or plumbed-in fridges. Without them, you might have to shut off the water to your whole house just to fix a small leak.
- Install individual shut-off valves.
- Use quarter-turn valves—they’re reliable and easy to operate.
- Test them occasionally to make sure they’re working when you need them.
4. Not planning for ventilation
Where things go wrong:
If your kitchen includes gas appliances, ventilation is critical. Without it, you can end up with condensation, mould—or worse, carbon monoxide issues.
What I recommend:
- Check that all gas appliances have proper ventilation—it’s a safety must.
- Install a ducted rangehood that vents outside—not just into your ceiling cavity.
- Use exhaust fans if your kitchen gets steamy.
5. Overloading the hot water system
Why it’s a problem:
Adding a butler’s pantry, a second sink, or even a new dishwasher can stretch your hot water system beyond its limits—leaving you with cold showers or long wait times for hot water.
Here’s how to avoid it:
- Insulate your hot water pipes to maintain temperature and reduce energy use.
- Make sure your hot water system has enough capacity for the new kitchen layout.
- If needed, upgrade or switch to continuous flow for better performance.
6. Forgetting about drainage slope
Why it matters:
Proper slope in your drainage pipes is what keeps water (and smells) flowing away properly. If it’s wrong, you can end up with slow drains or even backflow.
My fix:
- Ensure a minimum 2% slope on horizontal pipes—about 20mm per metre.
- Use larger diameter pipes for long runs.
- Have a plumber (like me) double-check it before everything’s sealed up—easier to fix now than after your new kitchen’s installed.
Plan your plumbing right from the start
Kitchen renovations are exciting, but don’t let plumbing be an afterthought. With the right planning and advice, you can avoid surprise costs and keep your project on track.
If you’re about to start a reno—or you’re in the thick of one—it’s a great time to get a plumber in to review your layout and give you some clear direction.
Need help planning your kitchen plumbing?
I’m here to make it easy. Give me a call on 0488 097 697 or book a service online. Let’s get your plumbing sorted—so you can focus on building the kitchen you’ve been dreaming of.
FAq's
What are the three most common types of plumbing in a home?
- Water Supply Lines:
Carry drinking water from the mains to faucets, showers, toilets, and other points of use. - Drain, Waste, and Vent (DWV) System:
Removes wastewater and gases from the sewer system, properly venting them to the outdoors. - Gas Lines:
Distribute natural gas or propane to appliances such as stoves, water heaters, and space heaters.
What are the most common types of pipes and fittings in home plumbing?
1- Pipes:
- Copper: Durable and corrosion-resistant. It is ideal for hot and cold water.
- PVC (Polyvinyl Chloride): It is inexpensive and common in cold water and drainage systems.
- PEX (Cross-linked polyethylene): It is a flexible and easy-to-install material. It is suitable for hot and cold water.
- Galvanized steel: It was once commonly used, but is now being replaced due to its tendency to corrode.
- ABS (Acrylonitrile Butadiene Styrene): This black plastic pipe is used in drains and ventilation.
- CPVC (Chlorinated PVC): It is very similar to PVC, but it resists high temperatures. It is very useful for hot water.
- Stainless steel: This type of pipe is highly resistant to corrosion and can be used in a variety of ways in the home.
- Black pipe: This is used for gas lines.
2- Fittings:
- Elbows: These change the direction of water flow.
- Couplings: Used to join two straight sections of pipe.
- Tees: Create a branch or branch in the line.
- Reducers: Used to connect pipes of different sizes.
- Unions: These facilitate easy disassembly.
- Bushings: Help reduce a larger pipe to a smaller one.
- Adapters: These allow connecting pipes of different materials.
- Caps: Allow the end of a pipe to be sealed.
- Plugs: Allows the sealing of a threaded opening.
- Flanges: Help connect pipes to equipment or systems.
