Summary

An outdoor tap looks like a 90-minute job: tee off the cold water under the kitchen sink, drill a hole through the wall, fit a brass bib tap, done. The compliant version takes longer because of the regulatory and seasonal-protection requirements that any halfway-experienced plumber should be building into the price.

The Water Supply (Water Fittings) Regulations 1999 require backflow protection on every outside tap, because the hose attached to it is a Fluid Category 3 risk (the hose end might sit in a bucket of fertilised pond water or weed killer). A double-check valve (DCV) inline immediately after the take-off provides that protection. A typical brass DCV is £8–£15 in materials, but its absence is the single most common compliance failure on otherwise reasonable outdoor tap jobs.

The other recurring cost is winterisation: an outside tap that can't be isolated and drained will burst its pipe in the first hard frost, and the call-back is usually free. Adding an isolation valve indoors and a drain-down outdoor tap, or specifying a frost-resistant outside tap, costs £20–£40 in materials and 30 minutes of labour, and saves the relationship with the customer for years to come.

For tradespeople the pricing question is: do you fit a basic compliant tap for £150–£200 (and walk away from the call-backs in February) or do you fit a proper winterised installation for £250–£400 and bank on the recommendations? The latter is the sustainable answer.

Key Facts

Quick Reference Table

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Job Type Materials Typical Labour Hours Typical Customer Price
Basic compliant outside tap (brass bib, DCV, isolation) £35–£65 1.5–2.5 £140–£280
Frost-resistant winterised tap £55–£120 2.5–4 £220–£420
Outside tap with separate run from rising main £80–£180 3.5–5.5 £350–£600
Tap with long external pipe run (e.g. to garden) £150–£350 5–10 £450–£900
Outside tap + separate hose reel + drain off £100–£200 4–6 £400–£700
Component Cost (Trade) Notes
Brass bib tap, 1/2" BSP £8–£18 WRAS-approved (e.g. Pegler, Reliance)
Frost-resistant bib tap £35–£90 Aquaflow, ProTap, Surestop
Double-check valve (DCV) £8–£15 15mm compression or push-fit
15mm full-bore isolator £4–£8 Lever type, indoor
15mm copper pipe per metre £4–£8 Plus fittings
15mm push-fit pipe + fittings £6–£12 Faster than copper, slightly higher material cost
Wall sleeve / grommet £2–£5 Stops pipe rubbing on masonry
Frost insulation jacket £4–£10 For outdoor tap body
Mastic / external sealant £4–£8 Weather seal both sides of penetration
Core drill 18–25mm £8 (consumable) If hiring kit, add hire cost
Variable Effect on Price
Solid brick wall vs cavity wall Cavity wall: more attention to sleeving and condensation, +£15–£40
Stone or rubble wall Specialist drilling, +£40–£80
Existing accessible cold pipe vs boxed-in Boxed-in adds 30–60 min stripping/refit + £40–£80 making good
Long run from rising main to outside wall +£30–£50 per metre of new run
Conservation area / listed building Survey + LPA notification, +£100+
Customer wants outside tap on a wall with no inside access (e.g. shed) MDPE supply run job, prices differently

Detailed Guidance

The Compliant Baseline

Every outdoor tap must include:

  1. Indoor full-bore isolator immediately downstream of the take-off (so the supply can be turned off without going to the main stopcock)
  2. Double-check valve (DCV) immediately downstream of the take-off, before the pipe leaves the heated envelope of the building
  3. Adequate insulation on any external pipework
  4. Sealed wall penetration (mastic both sides, sleeved if running through masonry)
  5. WRAS-approved fittings throughout (don't fit a "garden centre" tap of unknown provenance)

These are not options. The double-check valve in particular is a legal requirement under the Water Supply (Water Fittings) Regulations 1999. A water authority compliance check (often triggered by a neighbour's complaint, a new supply meter, or a property sale) will fail a tap without one.

Pipe Route

Three common geometries:

Kitchen back wall — Take off the cold supply under the kitchen sink, run 30–60cm horizontally to the wall, penetrate the wall, tap on outside. The simplest job; 1.5–2.5 hours.

Utility/garage external wall — Often the cleanest route because the indoor pipework can be surface-clipped without aesthetic concern. Same hours as kitchen back wall, but easier work.

Front of house / driveway tap — Often requires a longer run inside the house (under floorboards, behind kitchen units) to reach the rising main and then back out through a different wall. 3.5–5.5 hours; price as a separate run.

Far end of garden — A separate water supply job, not an outside tap. 25mm MDPE buried at 750mm depth, with an indoor stopcock and outdoor pillar/standpipe. Quote separately at £600–£1,500+ depending on garden length.

Frost Protection — Where Most Outdoor Taps Fail

A standard brass bib tap is not frost-resistant. In a hard winter (e.g. -5°C overnight), water trapped in the bib tap and the external pipe section freezes, expands, and either splits the tap body or the copper pipe inside the wall. The first warm day, the tap is opened and water floods into the wall cavity or down the inside of the kitchen.

Two acceptable winterisation approaches:

  1. Frost-resistant outdoor tap (e.g. Aquaflow Frost-Free, ProTap Frost-Free). The tap is designed with the valve mechanism set back into the wall at the warm-side insulation line, so when closed the entire external section drains down through the spout. Cost premium £30–£70 over a standard bib tap; minimal additional labour.

  2. Standard bib tap with seasonal isolation and drain-down. The customer turns off the indoor isolator in October, opens the outside tap to drain, and leaves the tap open through winter. Requires customer compliance; a drain-down cock immediately upstream of the wall penetration is best practice.

Approach 1 is the better answer for residential — no customer action required, no seasonal call-out. Approach 2 is acceptable where the customer specifically wants a particular tap style (Victorian bib tap on a period property, etc.) but build the maintenance instruction into the hand-over.

Tap Selection

Brass bib tap, 1/2" BSP, WRAS-approved — The default. £8–£18 from any plumbers' merchant. Use one that takes a serviceable washer and gland packing — not a "throwaway" tap.

Brass garden tap, 3/4" BSP — Higher flow, directly accepts a 3/4" hose connector without an adaptor. £15–£30. Better for customers who actually water a garden or fill a paddling pool.

Frost-resistant tap — £35–£90. Recommended for residential.

Recessed wall-mounted tap with hose reel housing — £80–£200. A neat finish for premium installs but requires a larger wall penetration and recess work.

Avoid: cheap chrome-plated brass taps with plastic internals (fail in 2–3 years); "frost-free" taps sold without manufacturer credentials (some are not actually frost-resistant); polypropylene-bodied taps (UV-degrade outdoors).

Worked Example: Standard Compliant Outside Tap

Job: New outside tap on the kitchen back wall of a 1980s semi. Cold supply taken from under-sink 15mm cold; 15mm copper through the cavity wall; brass bib tap with isolator and DCV indoors; mastic-sealed penetration; insulation jacket on tap body.

Item Cost
Brass bib tap 1/2" WRAS £14
15mm DCV brass £10
15mm full-bore isolator (lever) £6
15mm copper pipe + fittings £18
Mastic, sleeve, fixings £8
Insulation jacket £5
Materials subtotal £61
Labour 2.5 hours @ £55/hr £138
Core drilling (kit on van) £15
Brick dust clean up, hand-over £20
Labour subtotal £173
Subtotal £234
Markup 20% £47
Net price £281
VAT 20% (if registered) £56
Customer price (VAT-reg) £337

In real markets this sits at the middle of the £220–£420 winterised band; a non-VAT-reg sole trader would land near £280. A "cheap" outside tap quote of £80–£120 typically omits the DCV, the isolator, and any frost protection — and the customer pays for it later.

Make Good Properly

Most outdoor tap install complaints from customers are about the finishing:

Spend the last 20 minutes of every job tidying. Wipe the tap with white spirit, polish the brass with a microfibre, sweep the area, clean up the indoor cabinet you've been working in. This is what gets you the recommendation.

Frequently Asked Questions

Is a double-check valve really legally required?

Yes — Water Supply (Water Fittings) Regulations 1999, Schedule 2, paragraph 15 requires backflow protection appropriate to the fluid category. An outside tap with a hose attached is Fluid Category 3 (hose end may sit in fertilised water or contaminated ground), requiring Type EB protection (Double Check Valve or equivalent). A water company inspection will fail the installation without it.

Do I need to notify the water company?

In some regions yes — water companies operate Approved Plumber Schemes where the plumber self-certifies the work. Others require pre-notification for new fittings. Check the local supplier: Thames Water, Severn Trent, Yorkshire Water, etc. all publish guidance. A registered WIAPS (Water Industry Approved Plumber Scheme) member can self-certify in most areas.

Can I tee off the cold supply under the kitchen sink, or do I have to go to the rising main?

Either works, provided the take-off is on the cold supply (not a hot or boiler-fed circuit). Teeing off under the sink is simpler and lower-cost; the only constraint is that the pipe upstream is still potable cold water, which is true in any standard UK domestic install.

What's the difference between a frost-resistant tap and an "anti-frost" cover?

A frost-resistant tap has a mechanical design that empties the external section when closed — no water sits where it can freeze. An anti-frost cover (a foam jacket fitted over a standard tap in winter) just slows freezing; in a sustained cold spell it doesn't prevent it. Frost-resistant taps are the only reliable answer for UK climates.

Should I install the tap before or after the patio is laid?

Plan the tap position with the landscaper. Ideally fit the tap during first-fix when the wall is accessible and any paving allows the drip path to fall away from the wall. If the patio is already laid, position the tap so the drip falls onto a paving slab joint (mortar absorbs the water, not concrete) and consider a small drip tray to prevent staining.

Regulations & Standards