You might have been putting off replumbing your house for a long time because of the cost. It can be expensive, and you shouldn’t it do on a whim. But, sometimes, old plumbing must be replaced, especially if your home was built before the 1960s.
In the UK, the average cost of replumbing a house ranges from £13,000 to £20,000. But, the actual cost of replacing pipes in a house depends on its floor area, the number of bathrooms, and its accessibility. For a three-bedroom terraced house, the prices range from around £14,000 to £16,000.
In this guide, we’ll go into this in more detail, and hopefully, you’ll be better informed when the time comes.
Main Topics
How Much To Replumb a House?*
The figures in the table below show the cost of a total replumb, along with additional tasks you may consider.
| Task | Average Cost | Duration |
|---|---|---|
| Repiping 2-Bedroom Flat | £13,000 | 1 week |
| Repiping 3-Bedroom Terraced | £15,000 | 1 week |
| Repiping 4-Bedroom Semi-detached | £17,000 | 2 weeks |
| Repiping 5-Bedroom Detached | £20,000 | 3 weeks |
| New Central Heating Installation in 2-Bedroom House | £4,000 | 3 days |
| Replacement Central Heating Installation in 4-Bedroom House | £10,000 | 1-2 weeks |
| Replumbing/Repiping Bathroom | £1,700 | 5 days |
* Disclaimer – We compiled these amounts from various online resources. Therefore they are estimates and should be a starting point for your research. The cost of plumbing services varies depending on factors that we’ll discuss later. For accurate quotations and durations, contact a qualified plumber or use the form on this page.
Plumber’s day rates vary depending on the region where you live. Rates in London and southeast England may be up to 25% higher than elsewhere in the UK. Typically, the average hourly rate for a plumber is between £40 to £80 per hour. Sometimes, you might need a plumber at weekends. In these cases, plumbers charge a call-out fee for out-of-hours work. This is additional to the hourly rate and can be £120 or 50% of the total charge. Also, remember that plumbing work involving water heaters, whether gas or oil-fired, needs other qualifications, so the job might cost even more.
Replumbing a 3 Bedroom House Cost
For example, let’s look at a typical three-bedroom house and the cost breakdown for replumbing the property.
Assuming the overall repiping price is around £15,000, £6,000 will be for labour while the remainder (£9,000) will cover materials. However, this ratio varies depending on how easy it is to remove the old pipework, how easy it is to install the new pipework, and whether you can install it within cavities or on the surface.
Plumbers use standard 15mm pipes for mains pressure feed. And 22mm and 28mm pipes for loft pressure water feed. The standard lengths are 2m or 3m, and they must be joined using soldered or compression brass fittings. As you can imagine, a plumber can get through a lot of pipes and fittings over a standard-sized house.
- 15mm copper pipes cost from £10 per 3m.
- 22mm copper pipes cost around £20 per 3m.
- 28mm copper pipes cost around £30 per 3m.
- Copper/brass plumbing fittings from £2.50 to £20 each.
Replumbing a House
Every home is different, especially if you’re replumbing an old property. Therefore, you can’t follow a step-by-step plan. Instead, use the knowledge and experience of a qualified plumber who knows how to install the easy way.
Let’s look at the replumbing sequence as an overview.
Permissions
Usually, you won’t have any legal problems upgrading plumbing unless you build additional en-suites or extend existing bathrooms. First, check with your local authority that your home isn’t on the listed building register. You’ll need planning permission for altering the interior if it is.
All domestic repiping projects must comply with the current UK Water Regulations. Anyone can install plumbing, but you must know the regulations, and it’s an offence if you don’t comply. Therefore, it’s better if a registered plumber does the work. The plumbing installation must also comply with:
- Approved Document G of the Building Regulations.
- Drainage must comply with Part H.
- And Part J for water heating appliances.
Furthermore, it’s a legal requirement that only qualified professionals work on heating appliances. Heating engineers must be on the GasSafe Register for gas appliances or the OFTEC register for other fuels.
Plan the installation
Usually, old buildings didn’t have indoor plumbing when built. Instead, pipework and fittings were added later. Most old buildings have few natural and convenient cavities for pipework, so they would be installed wherever convenient, which might not be the best location.
The route for new water supply, central heating and drainage must be considered to run over the minimum possible distance without damaging architectural features such as fireplaces and plaster moulding. Also, many appliances need electricity such as electric showers, bathroom extractor fans etc. so you must allow for these too, and install the two services together.
Remove pipework
Remove the old pipework from within floor and ceiling cavities and walls. If this causes too many problems, pipework can be drained and left in place. If you intend to replace baths, sinks, basins and toilets, remove these now.
You now have a clean slate on which to work.
Installation
Plan installing pipes in accessible locations to be easily maintained when required. When lifting and replacing floorboards, ensure you don’t damage the new pipework beneath.
Avoid cutting floor joists when installing pipework, and don’t ever notch the joists as this will weaken their structural strength. Instead, bore holes through the centre.
Suppose you intend to lay carpet, many professionals draw the pipe and cable routes with paint or a permanent marker pen, so future trades know the locations of services. If this isn’t possible, make a plan of the pipe layout as a record for the homeowner.
If your house has hardwood feature floorboards, use a qualified carpenter to remove and replace them to prevent damage if mishandled.
Use brass screws rather than nails when replacing floorboards as they’re easy to remove. Another helpful tip is to create access hatches at pipe junctions to access the services.
Repiping, Cost Factors
Many factors affect the price the plumber charges for the repiping job:
Labour
Feeding copper pipes along cavities and under floorboards often needs two people. Therefore, most plumbers bring along an apprentice or labourer to help fetch, carry and do the unskilled jobs.
Flooring
Water pipes often travel under flooring. Therefore, lifting floorboards allows access at specific locations. Floorboards are easily lifted and replaced, but flooring grade chipboard or plywood is more complicated and takes longer, therefore costing more.
Radiators
While replumbing the water pipes, many householders decide it’s sensible to replace central heating pipes and radiators too. Modern radiators are better thermal conductors and provide more heat per square metre than old models. If your old radiators were single panel, it’s a good idea to install Type 22 radiators in their place (Type 22 means 2-panels and 2-sets of fins between the panels).
Pipe upgrades
Pipes and plumbing fittings come in different quality grades. Therefore, you should upgrade to the best quality you can afford.
Boxing in
Sometimes visible pipework is unavoidable. In this case, cover pipes with plywood or plasterboard boxes decorated to match the surrounding walls.
Water heater
If you have an out-of-date boiler, you probably can’t buy spares for it anymore, and your new central heating system likely won’t comply with the current regulations. Therefore, it’s common to buy a new boiler to match the size of your system.
Drainage
It’s not only water supply and central-heating pipes that wear out. Drainage pipes corrode, leak and eventually collapse too. Consider replacing the waste pipes while your house is in upheaval with repiping.
Moving pipework
Maybe it’s time to move the kitchen sink or the bathroom suite. You must move supply and drainage pipes from one location to another in both cases.
Loft work
If you live in a bungalow, you probably have all your water supply pipes and central heating circuit in the loft rather than underfloor. The pipework is easily accessed by removing the layer of loft insulation, therefore reducing the overall work.
Signs That Your House Requires Repiping
Generally, good quality plumbing lasts many years. But, over time, the pipe materials corrode and eventually, you have to change the pipework. The primary indicator is the age of the pipework. You can often find this information in the property details you received when buying your home or ask a reputable plumber to inspect the system and report its condition.
The following list gives pipe materials and their life expectancy.
PVC
Drain lines, made from PVC, are cheap and quickly assembled alternatives to the old fashioned lead or cast iron. PVC tends to last from 25 to 40 years.
Copper
Quality copper pipe makes good water supply lines. Copper is soft enough to use compression and soldered joints and lasts for 70 to 80 years.
Other metals
Before the 1960s, water supply pipes could have been made from galvanised steel, brass or lead. Although they last from 80 to 100 years, steel and brass corrode and eventually leak. They are also tricky to work with. All lead supply pipes should have been replaced by now as the metal leached into the drinking water, causing many long term health effects.
Waste pipes were made from cast iron or lead before the advent of cheap multipurpose plastics, and you might still find some in older properties, but these are now very rare.
Inspection
If your property is over 60 years old and has its original plumbing, you should regularly inspect for leaks, discolouration and flaking pipes. These are signs of pipe corrosion and indicate they need renewing.
Indicators such as these suggest the presence of cracks in the pipe structure or joints. Even if you only have one such leak, it’s a sign that the entire system is breaking down, and you should have your home replumbed before a major incident takes place.
Rust
If you have brown, red or yellow water from the kitchen or bathroom taps or have brown or yellow stains around the bathtub, you have rust in the pipes. The colour indicates the old pipework is corroding, and you should prepare yourself for a major leak. However, don’t confuse this with naturally occurring iron dissolved in the groundwater. Look on your local water company’s website for more information. Alternatively, the UK Government Environment Agency publishes safe iron levels in drinking water. A qualified plumber will know which scenario you have.
Poor water pressure
Over time, water supply pipes can build up a layer of contaminants on the pipe’s inner wall. Usually, it’s rust and suggests corrosion. However, in hard-water areas, this layer of limescale consists of insoluble calcium carbonate and can only be removed by chemical treatment. It usually appears inside water heaters, kettles and hot water pipes. The limescale reduces the thermal efficiency of radiators and boilers and generally restricts the pipe bore lowering the water flow rate. Although you can remove limescale chemically, it’s better to replace pipes that have suffered from limescale for many years. You can tell if you suffer from limescale by white chalky deposits around taps and showerheads.
Repiping House Q&A
Is it worth repiping a house?
Suppose you have never updated your plumbing and live in an old property. In that case, a potential buyer may insist on paying a lower amount because they know that old plumbing is a liability. And, even if you don’t want to move, older pipes have a greater chance of breaking, causing water damage and upheaval in your beautiful home.
Furthermore, old pipework has more chance of clogging up and lowering the water flowrate; this makes simple tasks like taking a shower and watering the garden a chore.
Can you plumb your own house?
Yes, you can. Except for water heaters and gas plumbing, anyone can carry out simple plumbing work in the UK. The only legal requirement is to comply with the UK Water Supply (Water Fittings) Regulations and Byelaws. Adherence to these rules ensures drinking water stays safe and isn’t wasted. Furthermore, many types of installations require approval by your local water supplier or the Building Control department in your local authority before you can start. If you aren’t sure whether your plumbing work needs approval, contact your water company, who will be pleased to advise you on where you stand.
Alternatively, use a WaterSafe registered plumber, trained in the strict regulations, who can install most types of plumbing without prior notification.
What size pipe should I use to plumb my house?
Mains pressure water needs 15mm pipework, whereas loft pressure requires 22mm diameter pipework.
Waste pipes, on the other hand, can vary in size depending on their application:
- 21.5mm used for overflows from cisterns and water tanks.
- Use 32mm for small washbasins or other low volume outlets.
- Kitchen sinks, showers and baths use 40mm pipe.
- Commercial buildings and apartment blocks use 50mm pipes.
- 110mm is a soil pipe used from the toilet and is the main drain pipe from a property.
Summary
Although replumbing your home can be an expensive task if done correctly, it always pays to replace your plumbing before it goes wrong. Water damage is always upsetting, and when one fitting starts to fail, the rest won’t be far behind. However, you must choose a reputable plumbing company with the appropriate qualifications and experience. And this isn’t always easy to do.
If you want to find a professional who will charge you a reasonable cost to replumb your house, complete the form on this page, and we’ll ensure you get up to four quotes for this project.