Electrics, plumbing and heating
Kitchen plumbing
Kitchen plumbing is the pipework that feeds and drains a kitchen: hot and cold supplies to the sink tap, cold feeds to the dishwasher, washing machine and any boiling water tap, isolation valves on each, and waste pipes with traps that fall steadily to the drain. On a refit it often also means moving a radiator or running new supplies to a new sink position.
When do you need kitchen plumbing?
Plumbing decides where the sink, dishwasher and washing machine can go. Moving the sink under a window, adding an island sink or fitting a boiling water tap all need new pipe and waste runs, and a radiator often sits exactly where a new run of units should be. Wastes are the tricky part: they need a steady fall to the drain, and in homes with solid concrete floors that can mean cutting a channel through the floor.
The survey visit records where the supplies, stopcock, waste stack and drain run are, and whether the floor is suspended timber or solid concrete. A plumber then first fixes the new pipework after strip-out, keeping joints where they can be reached behind units rather than buried in walls. Once the worktops are in, the sink, tap, valves, traps and appliance hoses are connected, and every joint is checked with the water running before the plinths go on.
What is included?
- A survey of the stopcock, supply pipes, waste route and drain connection
- Hot and cold supplies run to the new sink position
- Isolation valves on each tap and appliance feed for quick shut-off
- Dishwasher and washing machine supplies, with waste connections through suitable traps
- Waste pipes laid to a steady fall, with an access point for clearing blockages
- Radiators moved or replaced so they clear the new units
- A cold feed for a boiling water tap tank or a fridge with a water dispenser
- Redundant pipes cut back to the live supply and capped, then a full leak check
How much does kitchen plumbing cost?
These are national guide prices including VAT at 20%. Prices are higher in London and the South East and lower in much of the North, Wales, Scotland and Northern Ireland. Choose your area below for a local range.
| Typical project | Guide price |
|---|---|
| Sink, dishwasher and washing machine connectionsSupplies, valves and wastes in the new layout | £200–£500 |
| Sink relocated, or new supplies for a boiling water tapNew pipe and waste runs | £400–£1,000 |
| Waste run across a solid concrete floorChasing, pipework and reinstating the floor | £600–£1,500 |
| Radiator moved or replacedDrain down, new pipework and refill | £250–£500 |
Guide ranges cover labour, pipework, fittings, valves and traps; the sink, tap and appliances themselves, any gas work and any building control or building warrant fees are not included. Your price is confirmed after a free survey visit.
How long does it take?
Typical timescale: Half a day to 2 days, split between first fix and second fix. The programme for your kitchen is set out in the quote, and depends on the size of the room, what is moving, lead times for units and worktops and, after plastering, drying time.
Do you need permission or building regulations approval?
The rules differ across the UK. Choose your nation:
In England, kitchen pipework and fittings must meet the Water Supply (Water Fittings) Regulations 1999, which cover suitable materials, backflow protection and preventing waste or contamination of the supply. Connecting a sink to an existing waste or stack is routine, but a new connection to an underground drain, or a change to how waste water is discharged, involves building control. Gas pipework to a hob or cooker is separate work for a Gas Safe registered engineer.
Wales also follows the Water Supply (Water Fittings) Regulations 1999, so supplies, valves and appliance connections must use suitable fittings with the right backflow protection. Running a new waste to the existing stack is normally straightforward, while connecting to an underground drain or altering the way waste water leaves the house needs building control. Any gas pipe feeding a hob or range cooker can only be altered by a Gas Safe registered engineer.
In Scotland, water fittings are governed by the Scottish Water Byelaws 2014, which set comparable rules on materials, backflow and waste. Replacing a sink or rerouting pipework inside the kitchen does not normally need a building warrant, but a new connection to an underground drain, or a change to the way waste water is discharged, requires a warrant before any work starts. Gas pipework is separate and only for Gas Safe registered engineers.
In Northern Ireland, supplies and fittings must comply with the Water Supply (Water Fittings) Regulations (Northern Ireland) 2009. Reconnecting a sink or appliance to the existing waste is routine, whereas new connections to underground drains, or changing how waste water is discharged, need approval from the council's building control service under the Building Regulations (Northern Ireland) 2012. Gas work, including the pipe to a hob, is carried out only by a Gas Safe registered engineer.
What should you think about before starting?
- Find out whether the kitchen floor is suspended timber or solid concrete, as a waste run across concrete means cutting and reinstating the floor.
- Keep the sink near an outside wall or the existing stack where you can, because long waste runs need a fall the units must hide.
- Check your water pressure suits the tap you want, particularly a boiling water tap or a tall spray tap; the tap's instructions give its minimum.
- Put the dishwasher next to the sink so its supply and waste stay short, easy to reach and less likely to block.
- If a radiator sits where new units will go, decide early whether to move it, swap it for a tall one or fit a plinth heater.
- Ask for redundant pipes to be removed back to the live supply rather than left behind units, where they can hold stale water or leak.
How does the project run?
- Guide price. Use the online guide-price tool or call us for a realistic range for your area
- Free survey visit. We measure the room, check walls, floors and service positions, and look at the plan or delivery
- Itemised written quote. Broken down by stage and trade, with any worktop templating, engineer or approval costs listed
- Fitting in the right order. Strip-out, first fix, units, worktops, second fix and finishing, with the trades booked in sequence
- Final check and handover. A walk-round together, certificates for electrics and gas, and the manufacturers' documents
Questions about kitchen plumbing
How much does kitchen plumbing cost?
Connecting the sink, dishwasher and washing machine in a new layout usually costs £200 to £500 including VAT. Relocating the sink or running supplies for a boiling water tap is around £400 to £1,000, a waste run across a solid concrete floor £600 to £1,500, and moving or replacing a radiator £250 to £500. All are national guide prices, confirmed once we have seen the kitchen at a survey visit.
Can a kitchen sink be moved to a different wall?
Yes, usually. The supplies are the easy part; the waste decides it, because it needs a steady fall all the way to the stack or drain. On a suspended timber floor the pipe can often run between the joists, while on solid concrete a channel may need to be cut and filled. Where a fall cannot be achieved, a pumped waste is sometimes considered.
Why should every appliance have an isolation valve?
An isolation valve lets you shut off the water to one tap or appliance without turning off the whole house. If a dishwasher hose splits or a tap needs a new cartridge, you turn a small screw or lever under the sink and the rest of the home keeps running. Valves are fitted on the hot and cold tap feeds and on each appliance supply.
What plumbing does a boiling water tap need?
A boiling water tap needs a cold supply to a tank under the sink, usually through a filter, plus an electrical socket or spur for the tank. Some models also take hot and cold feeds for the mixer side. The tank uses cupboard space, so the sink unit is planned around it, and the tap's minimum water pressure is checked against your supply.
When does kitchen plumbing need building control?
Most kitchen plumbing does not. Replacing a sink, adding appliance connections and rerouting supply pipes inside the kitchen are routine. A new connection to an underground drain, or a change in how waste water is discharged, needs building control approval in England, Wales and Northern Ireland, or a building warrant in Scotland. Every fitting must also meet the water fittings rules for your nation.
What happens to the old pipes during a kitchen refit?
Pipes that will no longer serve anything are cut back to the nearest live pipe and capped, rather than left as long dead ends behind the new units. Water sitting in an unused length of pipe can go stale, and a forgotten joint can leak where nobody will see it. Old wastes are removed or sealed so they cannot let drain smells back into the room.
Related guides
Related kitchen services
Where do we carry out kitchen plumbing?
We take on kitchen plumbing across England, Wales, mainland Scotland and Northern Ireland. Choose your area for local guide prices and the rules that apply there.
England
- Bedfordshire
- Berkshire
- Bristol
- Buckinghamshire
- Cambridgeshire
- Cheshire
- Cornwall
- Cumbria
- Derbyshire
- Devon
- Dorset
- County Durham
- the East Riding of Yorkshire
- East Sussex
- Essex
- Gloucestershire
- Greater London
- Greater Manchester
- Hampshire
- Herefordshire
- Hertfordshire
- the Isle of Wight
- Kent
- Lancashire
- Leicestershire
- Lincolnshire
- Merseyside
- Norfolk
- North Yorkshire
- Northamptonshire
- Northumberland
- Nottinghamshire
- Oxfordshire
- Rutland
- Shropshire
- Somerset
- South Yorkshire
- Staffordshire
- Suffolk
- Surrey
- Tyne and Wear
- Warwickshire
- the West Midlands
- West Sussex
- West Yorkshire
- Wiltshire
- Worcestershire