Having a cold water tap on the outside wall of your house can make everyday tasks like washing the car or cleaning the patio so much easier – no more carrying heavy buckets through the house and spilling water all over the kitchen floor. Putting an extra tap on the outside wall of the house should only take a few hours, but you’ll need basic plumbing skills and tools for the job. If you’re a DIY novice, this might be a project too big for you, so it’s perhaps best to get the plumber in. If you think you can manage the job, here’s what you have to do.
Isolation Valves
Building regulations state that you must fit an isolation valve and a double check valve when you are putting a new tap on the exterior of the building. If you already have isolation valves and are just replacing one tap with another, there is no need to add additional valves. Before starting work to fit your tap, turn off the cold water at the valve, or at the stopcock under the sink if you don’t have isolation valves fitted. If you can’t find the stopcock you can also turn off the water in the street, but you will need a special spanner to do this.
Drilling Holes
It’s always easier to attach an outside tap in a location which is close to an existing cold water pipe. A common location is on the wall nearest a kitchen sink, or by a utility room back door. It is possible to put taps elsewhere, but this will mean more pipework and connectors. Once you have worked out where your cold water pipes are and where you want to position your tap, drill a hole in your external wall, leaving at least 25cm above the damp course. Use a drill bit wide enough to drill through the wall and to allow you to feed the tap through.
Joining the Pipes
Remembering to switch the cold water supply off, the next job is to join the new pipe for the outside tap to the cold water pipes feeding the sink. You will be using a T-piece connector to provide a new feed to the outside tap, so cut a large enough section to fit the connector. File the ends of the pipework until smooth, and make sure you tighten the connector piece fully. Fit another piece of pipe through the hole you have drilled in the wall and connect it up tightly to the T-connector.
Fit the Tap
Choose a tap from the wide range available at any DIY store, making sure you choose one which is suitable for use with the diameter of pipe you have fitted. Follow the manufacturer’s instructions and make sure everything is connected tightly before turning the water back on. Many large DIY stores and plumber’s merchants will have kits containing everything you need for the job and if you get stuck, there are lots of videos and online tutorials to walk you through the job step by step.
10 Frequently Asked Questions About Installing an Outside Tap
These frequently asked questions will help you understand the process and regulations involved in fitting an outside tap.
1. Do I need permission or building regulations approval to install an outside tap?
In most cases, no planning permission or building regulations approval is required to fit an outside tap. However, you must comply with UK Water Regulations, which include fitting a double check valve (to prevent backflow) and using appropriate pipework and insulation.
2. Can I install an outside tap myself?
Yes—if you’re confident with DIY plumbing, you can install an outside tap yourself. You’ll need to:
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Drill through the wall
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Tap into your cold water supply
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Fit a check valve and isolation valve
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Install the external tap and seal everything correctly
However, if you're unsure, it's wise to hire a qualified plumber.
3. Where is the best place to install an outside tap?
The best place is typically on a wall outside your kitchen or utility room, as it provides easy access to the cold water supply and minimises pipe runs. Shorter internal pipework also helps reduce the risk of leaks or freezing.
4. What tools and materials do I need?
For a standard installation, you’ll need:
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Outside tap kit (often includes backplate, hose connector, and fittings)
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15mm copper or plastic pipe and fittings
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Isolation valve and double check valve
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Drill with masonry bit and hole saw
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Pipe cutter
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PTFE tape and wall plugs
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Silicone sealant or expanding foam (for sealing the hole)
5. How do I connect the outside tap to my internal water supply?
Most commonly, you’ll use a self-cutting tap connector or T-fitting to splice into the cold pipe under your kitchen sink. From there, you'll run a pipe through the wall and connect it to the tap. Always fit a double check valve inside, just after the connection, to comply with UK water regs.
6. How do I prevent my outside tap from freezing in winter?
To protect the tap from freezing:
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Fit an internal isolation valve so you can turn off the supply in winter
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Use insulating pipe foam on indoor and exposed pipework
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Fit a tap cover or jacket on the outside tap during colder months
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Drain the pipe by opening the tap after shutting off the internal valve
7. Can I install a hot water outside tap?
Yes, but it’s less common. Hot water outside taps must be fitted in accordance with water regulations, with additional anti-scald measures and backflow prevention. For most purposes (e.g., garden use), cold water is sufficient.
8. Do I need a double check valve on an outside tap?
Yes—UK Water Regulations require all outdoor taps to be protected with a double check valve to prevent contaminated water from siphoning back into the mains. These are usually installed indoors, just after the cold water take-off point.
9. How much does it cost to install an outside tap?
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DIY installation: Around £20–£50 for a tap kit and materials
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Professional plumber: Typically £80–£150, depending on complexity and region
Getting a pro can save time and ensure compliance with water regulations.
10. Can I have more than one outside tap?
Yes! You can install multiple taps around your home if needed—such as front and back gardens. Each tap should be connected via appropriate pipework and protected with check valves. For longer runs, consider a dedicated pipe run and isolation valve for each tap.
Final Thoughts
Installing an outside tap is a manageable task for confident DIYers and a relatively affordable job for plumbers. Whether you’re tackling it yourself or hiring help, make sure to comply with UK Water Regulations, fit a double check valve, and protect your setup from frost damage in winter.
