Fit an outside tap — HomeGraft

Add a garden tap by tapping into your indoor pipework, drilling safely through the wall, and fitting a frost-proof outside tap.

OT-01Plan the tap position and check the rulesPick a spot on an outside wall close to the kitchen so the pipe run is short, ideally 400-450mm above ground level and clear of drains, air bricks or paving. UK Water Regulations (Water Supply (Water Fittings) Regulations 1999) require a backflow prevention device — a double check valve — on the pipe feeding any outside tap, to stop dirty garden water being sucked back into your drinking water. Sketch the route from an existing indoor pipe, through the wall, to the tap position, and gather your tools before you start.

RULES

1 each · Tape measure

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1 each · Spirit level

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KNOW THE RULES

Water Supply (Water Fittings) Regulations 1999 require a double check valve fitted on the supply to an outside tap. This isn't optional.

OT-02Turn off the water at the stopcockFind your stopcock, usually under the kitchen sink, and turn it clockwise until it stops. Open the kitchen cold tap to confirm the water has actually stopped before you go any further. Leave taps open around the house to drain down the system before you cut into any pipe.

OT-03Identify your wall type and choose your fixingsMost houses have solid brick or blockwork external walls, so the wall-plate elbow that holds the tap will usually fix straight into masonry with a Rawlplug and screw. If your house is timber-frame construction (common in newer builds), the outer wall may hide a timber stud or noggin behind the cladding — trace the fixing points with a stud detector or magnet, then drill a small pilot hole: timber dust means a timber stud, fine steel swarf means metal. Never fix a wall-plate elbow into a metal stud alone or into bare plasterboard — you need a solid timber stud, a noggin, or a fixing long enough to reach the masonry behind. If the internal wall you're teeing into is dot-and-dab plasterboard, plan for a gap of 20-40mm behind the board before you hit the block, and use fixings long enough to reach it.

1 each · Stud/cable detector

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OT-04Mark and drill the hole through the wallMark the drilling point on the inside wall and check it lines up with a sensible spot outside. Cables and pipes can run almost anywhere, not just near sockets and switches — sweep a detector over the wall, but still drill carefully and expect something to be there. Confirm your stopcock is off and turns freely so you can shut the water off fast if you nick a pipe; if there's any doubt about what's behind the wall, isolate the relevant circuit at the consumer unit first. In solid brick or block, drill a pilot hole from inside then a larger hole (around 32mm for a standard pipe sleeve) with a masonry bit at low speed, angling it very slightly downward towards the outside so rain runs away from the house. In a timber-frame wall, drill through the cladding and stud/sheathing with a long wood bit, aiming between studs for the hole itself but keeping a stud or noggin nearby for the fixing. Where the internal face is dot-and-dab or lath and plaster, drill slowly through the plasterboard or lath first — don't rely on either for support, only the masonry behind counts.

1 each · Masonry core drill bit, 32mm

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1 each · Long masonry drill bit

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OT-05Fit a wall sleeve through the holePush a length of plastic conduit or pipe sleeve through the hole to protect the pipe from the masonry edges and let it move slightly as temperatures change. Trim it flush on the inside and slightly proud on the outside so water sheds away from the wall.

1 each · PVC pipe sleeve, 22mm x 300mm

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OT-06Tee into the indoor pipe and fit the double check valveChoose a convenient point on the rising main or a nearby cold pipe — not one that only feeds a water softener or a tank-fed hot supply. Cut into the pipe, fit a tee, then fit an in-line double check valve just after it, following the flow arrow on the valve body. Add a small isolation valve on this new branch so you can shut off the outside tap alone in future without turning off the whole house.

RULES

1 each · 15mm copper equal tee

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1 each · Double check valve, 15mm

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1 each · Isolation/service valve, 15mm

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KNOW THE RULES

Water Supply (Water Fittings) Regulations 1999 require this double check valve — fitting a tap without one is not compliant.

OT-07Run and support the pipe to the wallRun 15mm copper or plastic pipe from the tee to the sleeve, using elbows to change direction as needed. Clip copper every 1.2m on horizontal runs (every 500mm for plastic pipe), and add a clip near every bend. Where the pipe crosses a stud wall on its way to the exterior, use a wood screw into a timber stud, a metal-stud-rated fixing into a metal stud, or a plug and screw into masonry — never a plain wood screw into a metal stud, it strips straight through.

3 m · 15mm copper pipe

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6 each · Pipe clips, 15mm

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OT-08Feed the pipe through and fit the wall-plate elbowFeed the pipe through the sleeve from inside, leaving enough proud outside to connect to the wall-plate elbow. Fit the elbow using the fixing that matches your wall type — a Rawlplug and screw for solid masonry, a wood screw into a stud or noggin for timber-frame, or a long fixing that reaches the block behind for dot-and-dab. Check it sits level with a spirit level before fully tightening.

1 each · Wall-plate elbow, 15mm

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2 each · Rawlplugs and screws

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OT-09Fit the tap and seal around the sleeveWrap the thread with PTFE tape and screw the outside tap onto the wall-plate elbow, tightening with a spanner — don't overtighten, the elbow can crack. Seal around the pipe sleeve on both the inside and outside wall faces with frost-resistant silicone to stop water tracking into the wall.

1 each · Outside bib tap

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1 each · PTFE tape

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1 each · Frost-resistant silicone sealant

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OT-10Turn the water back on and testTurn the stopcock back on slowly and open the new isolation valve. Check every joint you've made for drips, run the outside tap for a minute to clear any debris, and confirm the double check valve doesn't drip once the tap is shut.

OT-11Insulate the pipe and tidy upWrap the exposed pipe run, especially any section in a cold void or near the outside wall, with foam pipe insulation to prevent freezing. Fit an insulated cover over the tap itself for winter. Sweep up dust and offcuts, and make good any render or paintwork around the sleeve outside.

2 each · Foam pipe insulation, 1m lengths

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1 each · Outside tap cover

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