Whether you're renovating an existing laundry, adding one to a granny flat, or converting a spare space into a laundry for the first time, the plumbing behind it is more involved than most homeowners expect. It's not just a tap and a drain. Done properly, a laundry setup needs to handle washing machine connections, trough plumbing, floor drainage, and overflow protection, all working together so a hose failure doesn't turn into a flood.
Here's what a complete, compliant laundry plumbing setup actually involves.
1. Washing Machine Water Supply
Your washing machine needs both a hot and cold water connection, typically via a washing machine tap set mounted on the wall behind or beside the machine. A few things worth getting right:
- Use a proper washing machine valve, not a generic tap, since these are designed to handle the pressure fluctuations of a washing machine's fill cycles without wearing out prematurely.
- Consider a single-lever or timed shut-off valve if you're prone to forgetting to turn taps off, since a burst inlet hose while the water supply is left open is one of the most common causes of serious laundry water damage.
- Position taps for easy access, not squeezed in behind the machine where they're awkward to reach in an emergency.
2. Washing Machine Drain Connection
The washing machine's drain hose needs to connect to a properly installed standpipe or directly into the laundry trough's drain, with an air gap to prevent wastewater siphoning back into the machine.
Standpipe height matters.
If it's too low, wastewater can back up during the machine's drain cycle. If your standpipe seems to overflow during wash cycles, this is worth having a plumber check, since it's often an installation height issue rather than a blockage.
3. Laundry Trough Plumbing
If you're including a laundry trough or tub, it needs its own hot and cold supply and a drain connection, typically sharing the same waste line as the washing machine but with its own trap to prevent odours coming back up the drain.
Look for a trough with a decent-sized bowl if you plan to hand-wash items or soak clothes, since undersized troughs are a common source of buyer's remorse in laundry renovations.
4. Floor Waste and Drainage
Australian plumbing standards require a floor waste in laundries, an in-floor drain that catches any overflow, leaks, or spills before they can spread to adjoining rooms or through flooring. This is a compliance requirement, not an optional extra.
Correct fall matters here too.
The laundry floor needs a slight, even fall toward the floor waste so water actually drains rather than pooling. This is worth checking during any renovation that involves re-laying laundry flooring.
5. Overflow and Water Damage Protection
Given how much water passes through a laundry, and how often washing machines run unattended, a few extra protections are worth considering, especially if your laundry is on an upper floor or near living areas:
- A washing machine water damage prevention device, which automatically shuts off the water supply if it detects an unexpected flow pattern consistent with a burst hose
- A raised, sealed sill or step at the laundry doorway, so any significant overflow is contained rather than spreading into hallways or bedrooms
- Waterproof flooring and tanking, particularly important if the laundry sits above a lower floor or living space
6. Hot Water Delivery
If your laundry is a long way from your hot water system, check how long it takes hot water to reach the laundry taps. For a room used primarily for cold washes, this may not matter much. If you frequently use warm or hot cycles, it's worth discussing options with your plumber, including relocating the laundry closer to the hot water system or insulating the hot water line during a renovation.
7. Gas Connection If You're Adding a Gas Dryer
Gas dryers are less common than electric in Australia, but if you're planning one, it needs a dedicated gas line installed by a licensed gas fitter, which needs to be factored into the renovation plan early, the same way any gas appliance connection would be.
A Laundry Plumbing Checklist
Before finalising your laundry layout, confirm:
- Hot and cold supply valves are positioned for easy access, not hidden behind the machine
- The drain standpipe height is correct for your washing machine model
- A floor waste is included and has adequate fall
- The trough (if included) has its own trap and adequate drain capacity
- Waterproofing and flooring can handle occasional water exposure
- Hot water delivery time to the laundry is acceptable for how you'll use it
Get Your Laundry Plumbing Right the First Time
A laundry deals with more water volume and more unattended appliance cycles than almost any other room in the house, which is exactly why getting the plumbing right matters more than it might seem. A properly installed floor waste and correctly positioned standpipe are the difference between a minor hose failure being a non-event and it becoming a significant water damage claim.
Coastal Plumbing Professionals installs and renovates laundry plumbing for Gold Coast homes, from simple washing machine connections to full laundry renovations.
Call 1300 590 085 to arrange a laundry plumbing quote.
Frequently Asked Questions
Does a laundry legally need a floor waste?
Yes, Australian plumbing standards require a floor waste in laundries to catch overflow, leaks, or spills before they spread to other areas of the home.
Can I install my own washing machine plumbing?
Connecting an existing washing machine to already-installed taps and a standpipe is something many homeowners do themselves. However, installing new supply lines, drain connections, or a floor waste is licensed plumbing work in Queensland and must be done by a licensed plumber.
Why does my washing machine drain overflow during the wash cycle?
This is most commonly caused by an incorrectly installed standpipe, either too short or with inadequate air gap, causing wastewater to back up rather than drain freely during the machine's pump-out cycle.
Do I need a water damage prevention device for my laundry?
It's not a legal requirement, but it's a worthwhile investment, particularly for laundries on upper floors or near living areas, since a burst washing machine hose left running unattended is one of the most common and expensive household water damage events.
How much does a laundry plumbing renovation typically involve?
This depends heavily on whether you're keeping fixtures in their existing locations or relocating the trough, sink, or machine connections, and whether new floor waste and waterproofing work is needed. A plumber can scope this accurately once your renovation layout is set.
Resources
- AS/NZS 3500 Plumbing and Drainage Standards | Standards Australia
- Plumbing and Drainage Act 2018 | Queensland Government
- Water Efficiency Labelling and Standards (WELS) Scheme | Australian Government
