To plumb in a washing machine, you connect its fill hose to a cold water valve, put its drain hose into a standpipe or onto the spigot of a sink trap, level the machine, plug it into a wall socket and run a test wash while checking both ends for leaks. If the valve and waste point are already there, it is a straightforward DIY job that needs little more than a spanner and a spirit level, but if you need new pipework, a new waste or a machine in a new spot, that is plumbing work where a plumber saves time and leaks.

What you need

• The machine’s installation instructions (they overrule anything general, including this guide)
• The fill hose and drain hose supplied with the machine, plus the hook or guide for the drain hose
• An adjustable spanner, for the transit bolts if a tool is not supplied
• A spirit level
• A bucket and old towels
• A torch, for looking behind the machine and under the sink

You do not need PTFE tape on the fill hose. Washing machine hoses seal with a rubber washer inside the connector, and tape can stop the washer seating properly.

Check what you already have

Before you start, look at the space where the machine will go.

What you find	What it means
A valve on the cold pipe with a threaded outlet (often a blue lever)	Ready for the fill hose
Two valves, one hot and one cold	Most modern machines are cold fill only. Use the cold valve and leave the hot one off
A vertical waste pipe (standpipe) near the machine	Ready for the drain hose
A spigot on the side of the kitchen sink trap	Ready for the drain hose, once any blanking cap is removed
No valve and no waste	You need new pipework. See “Adding a new supply or waste” below

Step by step: plumbing in the machine

1. Remove the transit bolts. Manufacturers fit bolts (often three to five) through the back of the machine to hold the drum still in transit. Remove them with the supplied spanner, fit the plastic caps that come with the machine, and keep the bolts in case you move house.
2. Turn the water off at the valve. A washing machine valve turns off with a quarter turn: the lever across the pipe is off.
3. Connect the fill hose. Check the rubber washer is in place, then screw the hose onto the machine and onto the valve by hand. Tighten firmly by hand as your instructions describe. Overtightening with a spanner can crack the plastic nut or squash the washer.
4. Fit the drain hose. Clip it into the hook or guide supplied so it forms a curve at the top. For a standpipe, put the end in no more than about 15cm down. For a sink trap, push it onto the spigot and secure it with a hose clip, making sure the hose rises high under the worktop before it drops to the trap.
5. Check the drain height. The highest point of the drain hose must sit within the range your manual gives. Beko, for example, specifies a minimum of 40cm and a maximum of 100cm from the floor, while Samsung and AEG ask for at least 60cm. Too low and the machine can siphon water out while it fills. Too high and the pump struggles.
6. Slide the machine into place without kinking either hose. Leave a small gap at the back for the hoses.
7. Level it. Put the spirit level on top, front to back and side to side, and adjust the feet. Tighten any locking nuts. Rock each corner: the machine should not move.
8. Turn the water on slowly and look at both ends of the fill hose for drips.
9. Plug it into a wall socket. Manufacturers warn against extension leads for washing machines.
10. Run an empty rinse or short cycle. Watch the fill hose, the drain connection and the floor while it fills and drains. Check again after the spin.

Standpipe or sink trap: which is better?

Feature	Standpipe	Under-sink spigot
How it works	Hose drops into a vertical pipe with its own trap	Hose connects to a spigot on the sink’s trap
Main advantage	Independent of the sink, easy to reach	Uses the existing sink waste, often no new pipework
Watch out for	Pushing the hose too far in and causing siphoning	Leaving the blanking cap on the spigot, or food debris backing up
Good for	Utility rooms, machines away from the sink	Kitchens with the machine next to the sink

A washing machine and dishwasher can share one sink trap if it has two spigots, or a trap with a dual inlet. If the sink drains slowly once the machine is connected, the trap or waste may be partly blocked. Our blocked sinks and drains team can clear it.

Adding a new supply or waste

If there is no washing machine valve or waste, you will need to add them.

• Water supply: the neat way is to cut a tee into the cold pipe and fit a proper washing machine valve. Self-cutting valves that clamp round the pipe and pierce it are sold for DIY use, but they depend on a clamp seal around a hole in your pipe, so a properly fitted tee is the more reliable choice.
• Waste: either a new trap under the sink with a spigot, or a standpipe with its own trap connected to a suitable waste pipe.
• Backflow: the water regulations require appliances like washing machines to be protected against dirty water flowing back into the mains. Most machines listed by the Water Regulations Approval Scheme have backflow protection built in, but where and how a machine is installed can mean extra protection is needed, so check the manual.
• Pressure: manufacturers set a minimum supply pressure. Beko’s simple test is at least one litre every seven seconds from the tap feeding the machine. If your flow is weaker than that across the house, our guide to low water pressure in the whole house explains the likely causes.

Washing machines open and close their water valves quickly, which can make pipes bang. If you hear a thud from the pipes as the machine fills, our guide to banging pipes and water hammer explains what can be done.

If any of this is new territory, our general plumbing repairs service covers new valves, wastes and moving a machine.

Common mistakes that cause leaks and floods

• Transit bolts left in: loud banging and vibration on the first spin, and possible damage to the drum.
• Drain hose pushed too far into the standpipe: the machine siphons, emptying as it fills, so it never seems to finish filling.
• Blanking cap left on a new trap spigot: the machine cannot drain, or the hose pops off under pressure.
• Kinked hose behind the machine: slow filling, draining faults and error codes.
• Cross-threaded or overtightened fill hose: a slow drip that ruins the floor over weeks.
• Machine not level: walking across the floor on spin, noise and strain on the hoses.

What it costs with Vantage

In normal working hours there is no call-out fee. After the first hour, time is charged in half-hour steps, and parts such as a new valve, trap or standpipe are quoted before we fit them. Evening, weekend and overnight visits are charged at the out-of-hours rates. Every rate is published on our prices page, so you know what you will pay before we arrive.

Frequently asked questions

Can I plumb in a washing machine myself?

Yes, if there is already a washing machine valve and a waste point, most people can do it with a spanner, a spirit level and the manual. Adding new pipework, a new waste or moving the machine to a new room is more involved, and mistakes there tend to show up as leaks under the floor.

Do I need to turn the water off to plumb in a washing machine?

Turn off the washing machine valve before connecting or disconnecting the fill hose. If there is no valve, or you are cutting into a pipe to add one, turn the water off at the main stopcock and drain the pipe first.

Does a washing machine need hot and cold water?

Most modern washing machines are cold fill only and heat their own water. If your machine has a single fill hose, connect it to the cold valve. Check the manual if your machine has two inlets.

How high should a washing machine waste pipe be?

It depends on the machine, so check the manual. Beko asks for the highest point of the drain hose to be between 40cm and 100cm from the floor, while Samsung and AEG ask for at least 60cm. The hose should go no more than about 15cm into the standpipe.

Why does my washing machine keep draining while it fills?

That is siphoning. It usually means the drain hose is too low or pushed too far into the standpipe. Raise the top of the hose into the range your manual gives and pull it back so no more than about 15cm sits inside the pipe.

Help with washing machine plumbing in Hertfordshire

If you need a new valve, a new waste, a machine moved or a leak traced, our plumbers can do it in one visit. We cover Hertfordshire, Bedfordshire and Cambridgeshire from our base in Stevenage. Book through our general plumbing repairs page or call 01462 506374.