How To Replace An Outside Tap Step By Step
Swap a leaky or tired garden tap for a new one using an adjustable spanner and a roll of PTFE tape.
The short answer
To replace an outside tap, turn off the water supply to the tap and open it to drain the pipe. Unscrew the old tap anti-clockwise with an adjustable spanner, clean the threads on the wall plate, wrap the new tap's thread with PTFE tape, then screw it in by hand and finish with the spanner. Turn the water back on and check for leaks.
Outside taps take a battering from frost and sun, and sooner or later they start to drip from the spout or seize up so they're hard to turn. Swapping one for a new tap is one of the simpler plumbing jobs around the house, because the new tap screws straight into the existing wall plate and you don't need to touch the pipework.
We replaced the tap on the rendered wall at one of our properties for this guide and photographed each stage. As long as the old tap comes off without a fight, it's a short job with basic tools.
Tools And Materials For The Job
- A new outside tap with the same thread size as the old one
- An adjustable spanner, plus a second one for bracing the wall plate
- PTFE thread seal tape
- Fine sandpaper or a wire brush for cleaning the threads
- A rag for wiping away water and old tape
Before You Start
Check the thread size of the old tap before you buy a replacement. Most garden taps are a standard half inch fitting, and confirming yours first means the new one screws straight into your wall plate.
Outside taps also need protection against water being drawn back into the mains, which is a requirement of the UK water regulations. Many new outdoor taps come with a double check valve built in, so look for this on the packaging if your existing setup doesn't have a separate one on the pipe.
How To Replace An Outside Tap
1. Turn Off The Water Supply
Isolate the water before you go near the tap. Look first for a dedicated isolation valve on the pipe feeding the outside tap, under the kitchen sink or close to where the pipe passes through the wall. If there isn't one, turn off the internal stopcock, and as a last resort use the external stopcock under the small metal cover in the pavement or path outside your property.
Once the supply is off, open the outside tap and let it run until it stops. There can be a surprising amount of water sitting in the pipe, and draining it now saves you a soaking when the tap comes off.
2. Unscrew The Old Tap
Grip the body of the old tap with an adjustable spanner and turn it anti-clockwise. How easily it moves depends on how long it's been on the wall. Ours needed a lot of force before it gave, and once it loosened we could spin the rest of the way off by hand.
Brace the wall plate with a second spanner while you turn, so the force goes into the tap and not into the pipe behind it.
3. Clean The Wall Plate Threads
With the old tap off, look inside the wall plate. You'll find old PTFE tape, limescale or grit around the thread, and it all needs clearing so the new tap seats properly. A rag deals with most of it, and a light rub with fine sandpaper shifts anything that's stuck on.
This is also the moment to check the wall plate itself is still firmly screwed to the wall and isn't cracked.
4. Wrap The New Tap With PTFE Tape
Wind PTFE tape around the thread on the new tap, wrapping in the same direction you'll screw the tap in so the tape doesn't bunch up and unravel. We went round the thread 10 to 15 times to get a good, watertight seal, as the photo shows.
5. Screw In The New Tap
Start the new tap by hand so you can feel it catch the thread cleanly. If it resists in the first turn or two, back it off and start again, because a cross-threaded tap will leak. Once it's running smoothly, finish tightening with the spanner until the spout points straight down.
6. Turn The Water On And Check For Leaks
Restore the supply, run the tap and watch the joint with the wall plate for any drips. We fitted a Hozelock connector onto the new tap so we could test it with the garden hose on a reel straight away, but a bucket or watering can does the same job.
If the joint weeps, turn the water off, take the tap back out and add a few more wraps of tape before refitting.
Fitting An Outside Tap Where There Isn't One
Adding a tap to a wall that's never had one is a much bigger job than a straight swap. You'll need to drill through the external wall with an SDS drill for brick and block and a long masonry drill bit, then cut into the cold water pipe indoors and run a new branch out to the wall plate with an isolation valve and backflow protection.
None of that is especially difficult for someone who's cut and joined pipe before. If you haven't, we'd leave a brand-new outside tap to a plumber and stick to replacing existing ones yourself.
When The Old Tap Won't Come Off
A seized tap is the only real snag with this job. Limescale, paint and old tape lock the thread over time, which is why so many old taps put up a fight. A larger spanner gives more leverage, and a spray of penetrating oil left to soak for a while helps free the thread.
Keep the wall plate braced with a second spanner the whole time. If the plate twists, it can strain or crack the joint on the copper pipe behind it, and you've turned a simple swap into a leak inside the wall.
Getting More From Your New Tap
A tap that turns freely and doesn't drip makes every garden job easier, from filling a watering can to running the hose and pressure washer for jobs like cleaning patio slabs each spring. In winter, disconnect the hose and fit an insulated cover over the tap to stop it freezing.
What People Also Ask Us
Do you need a plumber to replace an outside tap?
No, replacing an existing outside tap is a job most homeowners can do themselves with an adjustable spanner and PTFE tape. The new tap screws into the existing wall plate, so there's no pipe cutting involved. A plumber is worth calling if the wall plate is cracked, the pipe behind it is damaged, or you want a tap fitted where there isn't one already.
Which way do you wrap PTFE tape on an outside tap?
Wrap PTFE tape in the same direction that the tap will turn as you screw it in, which is clockwise when you're looking at the end of the thread. Wrapping this way means the tape tightens onto the thread as the tap goes in rather than peeling off and bunching up. Keep the tape taut and overlap each turn slightly.
Why is my new outside tap leaking at the wall?
A new outside tap leaking where it meets the wall plate comes down to too little PTFE tape, old tape or dirt left in the wall plate, or a cross-threaded fitting. Turn off the water, unscrew the tap, clean both threads and rewrap with more tape. Start it by hand so it catches cleanly before you tighten it with the spanner.
Do outside taps need a double check valve?
Yes, UK water regulations require outside taps to have backflow protection, which stops dirty water from a hose being drawn back into the mains supply. A double check valve does this job, either built into the tap or fitted on the pipe feeding it. Many replacement outside taps include one, so check the packaging before you buy.
What do you do if the old outside tap won't come off?
A seized tap is the only real snag with this job. Use a larger spanner for more leverage, and spray penetrating oil on the thread and leave it to soak. Keep the wall plate braced with a second spanner the whole time, because if the plate twists it can strain or crack the joint on the copper pipe behind it.
How do you test a new outside tap without a hose?
A bucket or watering can does the same job as a hose. We fitted a Hozelock connector onto the new tap so we could test it with the garden hose on a reel straight away. Run the tap and watch the joint with the wall plate for drips. If it weeps, turn the water off and add a few more wraps of tape.
Can I fit an outside tap where there isn't one?
Adding a tap to a wall that's never had one is a much bigger job than a straight swap. You need to drill through the external wall, cut into the cold water pipe indoors and run a new branch out with an isolation valve and backflow protection. If you haven't cut and joined pipe before, leave a brand-new tap to a plumber.
How do I protect an outside tap in winter?
Disconnect the hose and fit an insulated cover over the tap to stop it freezing. Outside taps take a battering from frost and sun, and that's why they start to drip from the spout or seize up. A tap that turns freely and doesn't drip also makes it easier to feed a hose or pressure washer in spring.
Richard has spent years renovating properties and turning them into rentals and Airbnbs. Like a lot of people he started out as a beginner, and these days there isn't much DIY he won't take on.