How to fit an outside tap

Video by Plumberparts. This walk-through draws on the video "HOW TO FIT AN OUTSIDE TAP - Plumbing Tips" from Plumberparts, which covers the full installation from choosing a position and drilling the wall through to connecting the copper pipework. The section on running the pipe from the kitchen cold supply and fitting the check valve is particularly worth watching before you pick up the drill.

1. Choose the position and check the regulations

The ideal spot for an outside tap is directly behind the kitchen cold-water supply pipe — or as close to it as possible. Less pipe run means less work, fewer potential leak points, and a quicker job. Mark where you want the tap on the outside wall first, then check from inside that you are not about to drill straight through a joist, a cable, or a buried pipe.

One thing worth knowing before you start: water regulations require a double check valve on any outside tap connected to the mains. This stops dirty water from a hosepipe or garden sprayer being siphoned back into the drinking supply. It is a legal requirement, not an optional extra — and the kind of thing a water company inspector will look for if they ever check.

2. Gather tools and materials

You will need a bib tap (a standard threaded outside tap), a wall-plate elbow or back-plate elbow to mount it, 15 mm copper pipe or push-fit pipe and fittings, a double check valve, an isolating valve, PTFE tape, a pipe cutter, a masonry drill bit sized to your pipe (typically 20 mm or so to allow a sleeve), and a good SDS drill for the wall.

Pick up some pipe lagging for the run inside the house too, especially if it passes through an unheated void. East Kent winters are mild compared with further north, but a cold snap can still freeze an exposed pipe near an external wall. To be fair, it rarely causes trouble in most houses around Sandwich — but it only takes one hard frost to split a joint.

3. Drill through the wall

Mark the drill position outside — go for somewhere that keeps the tap at a comfortable working height, usually around 300 mm above ground level. Drill from outside inwards where you can; it gives you better control of where the hole breaks through inside the house. Use a long masonry bit and keep the drill as level as possible. A slight downward angle toward the outside face is no bad thing — it helps any moisture drain out rather than in.

Once through, push a length of pipe or a plastic sleeve through the hole to protect the copper from the masonry. If there is a cavity wall, check whether insulation is packed in tight, as drilling through a filled cavity can get messy. Clear any debris from the hole before threading the pipe.

4. Fit the isolating valve and double check valve

Turn the mains water off at the stopcock before touching anything. On the cold supply inside, cut into the pipe at a convenient point close to where your new tap run will branch off. Fit a tee piece, then run 15 mm pipe from the tee toward the wall. Add the isolating valve first — this lets you shut the outside tap off completely in winter without affecting the rest of the house — then add the double check valve downstream of it.

The check valve has a flow direction marked on it; fit it the right way round. Tighten compression fittings firmly but do not go mad — copper is soft and over-tightening will damage the olive inside the fitting. If you are using push-fit, make sure the pipe is deburred and fully seated before you move on.

5. Connect the tap to the outside wall

Thread the pipe through the wall and connect it to the wall-plate elbow on the outside face. Screw the elbow to the wall with rawlplugs and screws appropriate for the masonry — solid brick walls around Sandwich are common and generally straightforward to fix into. Apply PTFE tape to the threaded male connection, winding it clockwise four or five times so it does not unwind when you screw on the tap.

Screw the bib tap onto the wall-plate elbow and tighten with an adjustable spanner. You want it snug, not forced. The tap spout should end up pointing slightly downward so water drains clear of the wall. Seal around the pipe where it exits the wall with exterior-grade silicone to prevent damp tracking in — a small step that many people skip, and then wonder why the plaster inside is damp the following winter.

6. Turn the water back on and check for leaks

With everything connected, open the isolating valve slowly and let the system pressurise. Check every joint inside — the tee, the check valve, and any compression fittings — before going outside. Run your hand around each one and wait a minute. Even a tiny bead of water forming on a fitting is worth dealing with now, while access is easy.

Open the outside tap to clear any debris from the pipe, then close it and check the wall-plate elbow connection too. Mark the isolating valve position with a waterproof label so that whoever uses the house in future knows where to find it. In winter, close the isolator and open the outside tap briefly to drain any remaining water in the pipe — that is all the winterisation an outside tap normally needs.

When to call a handyman

Call Richard if you are not confident cutting into your existing plumbing, if the stopcock is seized and will not close, or if the wall between your kitchen and garden is more than about 300 mm thick (a few older properties in and around Sandwich have unusually deep walls that need a longer sleeve arrangement). Fitting an outside tap is also one of those jobs that tends to reveal other issues once you open up the pipework — old compression joints, corroded pipe, or a stopcock that barely works — and having someone on hand who can deal with those as they come up saves a lot of fuss.