Installing an Outside Tap — DIY Guide
Check the steps below first — if you're not confident, get it fixed safely today.
Post a job — we'll find you an engineer →You must fit a double check valve (non-return valve) to any outside tap connection to comply with Water Regulations 1999 — this prevents garden hose water from being siphoned back into the mains supply.
An outside tap is one of the most useful home additions for UK gardens. It is a realistic DIY project for someone comfortable with basic pipework. The most challenging part is drilling through the external wall — everything else is straightforward compression or push-fit pipework.
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Choose the tap location — ideally on a wall close to the kitchen or utility room where the cold supply pipe runs, to minimise the length of new pipework needed. The tap should be positioned at a height that allows for a hosepipe to attach easily (about 400–600mm from ground level).
Turn off the cold water supply at the stopcock. Identify the cold supply pipe in the kitchen or utility room — this is the pipe you will T off from. Drain the pipe by opening a cold tap elsewhere in the house.
Drill a 22mm hole through the external wall using a masonry core drill bit. Angle the hole slightly downward (5°) toward the outside so any water in the pipe drains away when the tap is turned off. Use a dust sheet inside and be prepared for dust.
Fit a 15mm T-piece on the cold supply pipe using compression fittings. Run 15mm copper or plastic pipe from the T-piece through the wall to the outside. Clip the pipe to the wall at 500mm intervals.
On the inside, before the wall, fit a double check valve (backflow preventer) — this is a legal requirement. Also fit an isolating valve so you can turn off the outside tap in winter without affecting the kitchen supply.
On the outside, connect the pipe to an outside tap body using a compression fitting. The tap body should be fixed to the wall with appropriate masonry fixings — use a stainless steel wall plate elbow for a neat finish.
Turn the water back on, open the outside tap and check for leaks at every fitting. When winter approaches, turn the outside tap off at the isolation valve inside and open the outdoor tap to drain the pipe.
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