Can You Add A Bathroom Anywhere In A House? | Advice & Information

Absolutely! However, the real question has more to do with if you should add the bathroom just anywhere. Building a bathroom requires more than just a few square meters of space. When you add a bathroom in the right place to an existing home, it can be a fairly affordable upgrade. Put it in the wrong place and a tiny cloakroom could come with an exorbitant price tag.

In this post, I’ll cover why you might want to add another bathroom to your house as well as the considerations you will need to take into account. So you can decide if it’s the best choice for you.

Let’s get into it!

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Why Would You Want To Add Another Bathroom To A House?

How often have you stood outside the bathroom door waiting for someone to finish their marathon shower? The most common reason for adding a bathroom is comfort and convenience. One more sink, toilet, and shower can alleviate the stress of the morning traffic jam in a busy home.

Also, entertaining friends and family is much easier when there is a bathroom located off the front hall. There is no need to share your private space with the whole world.

Fortunately, adding a bathroom will also add value to your home. According to a report by Nationwide. An extra bathroom adds 5% to the value of the average home. So, if you’re home is valued at £250,000 that means an additional bathroom could increase your house price by £12,500.

Depending on the amount of work needed and the spec of the new bathroom, this could easily cover the costs of the upgrade. Making it a worthwhile investment in the long run. Additionally, buyers are much more likely to make an offer on a home with even an extra half bath compared to just the one main bathroom.

Add A Bathroom Anywhere In A House

What To Consider When Adding A Bathroom To A House

While it is completely possible to add a bathroom anywhere in a house there are a few very important considerations to take into account.

How Much Room Is Needed To Add A Bathroom

The average size of a bathroom in the UK is just over 4.4 square meters, which really doesn’t give you a lot of elbow room. You can squeeze a two-piece powder room into less than 3 sq. m. If you are planning a spacious spa, you will want to set aside more than 5 square meters.

When measuring out an existing closet, remember that you will need at least 550mm between the front of the toilet and the wall, but 750mm allows for a more comfortable visit to the WC. Look at the location of the door and ensure that it will not swing in and block your ability to get in and out of the room.


One of the most popular spots to pop a new bathroom into an existing home is under the front stairs, often replacing an awkward closet with a compact sink and toilet. You may want to fit one in between two bedrooms, removing some living space and replacing it with a shared suite.

Underutilised coat closets and pantries may have enough room to fit in a three-piece bath. Do you have a connected garage? You may be able to shave a few meters off the back to pop in a mixed-use bath and laundry.

All of these are smart solutions to your morning fight for a shower and sink. But before you start knocking down the walls, you will want to consult with a licensed plumber and an engineer who can help you work out where all the pipes will run and if there are any restrictions on weight limits due to the joists (if located above the ground floor).

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Plotting Out A Path For Water And Waste

The easiest and most cost-effective way to add a bathroom is to locate your existing waste and water supply pipes and plan to position the new bath on the same wall. Most homes built in 1950 or later feature a wet wall with most of the kitchen, bath, and laundry pipes all situated in the same area. This ensures minimal demolition of walls and ceilings throughout the home.

If you have heating radiators, you will need to make a plan to extend the pipes to add a new unit in the new space.

Connecting To The SVP (Soil & Vent Pipe)

The most important service that your bathroom provides is whisking waste away to join the city sewer system (or septic tank). Your home’s main connection to the city cannot be moved. You will need to run all your drain pipes so that they join the SVP without cutting through the supporting structure. If you are installing a second-floor bathroom, you may need to have floor joists reinforced to accommodate a new pipe running through the walls. 

Do you live in an older home? You may have an external SVP. You will need to check with local regulations to see if your new bathroom pipes could also run on an exterior wall to join the SVP.


If you have ever lived in a high-rise flat, you probably had a bathroom with no windows. Did you struggle to keep the room free of mould and mildew? That is due to a lack of ventilation and natural light.

Your new bathroom is required to have an exhaust fan. The simplest way to exhaust a bathroom is a direct-vent fan mounted in the exterior wall. But you can exhaust an interior WC by running a duct from the room through the ceiling or floors to the outside.

Even a small window will bring sunlight into the tight space. The UV light prevents mould from taking hold and growing in a damp room.

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Can You Put A Toilet Anywhere In A House?

Yes, you can put a toilet anywhere in a house. However, as with a bathroom, its location will be key in determining how easy and cost-effective it will be to install.

Access to a water feed and the SVP are crucial for adding a toilet. So, it’s these serveces are close by to tap into then it can be a relatively quick and cost-free upgrade. However, if the SVP is the other side of the house, trying to run a new one or connect up to the existing one could be tricky and very costly.

This doesn’t mean that it’s impossible to add a toilet anywhere in a house. A macerator (or up-flush) toilet may be the perfect solution.

Macerator Toilet: How Does it Work? 

When you want to install a toilet in your house but it’s the complete opposite end to your home’s SVP and you can’t run a new SVP to connect up to the existing one. Or, when you have to place a toilet or bathroom lower than the connection to the city sewer and there is nowhere for the waste to flow downhill. A macerator toilet can be the solution to these problems.

A Macerator toilet fixes the problem by collecting waste in a chamber, grinding it up into a liquid, and then uses a pump to push the waste up and out to join the SVP. However, as the waste is ground up it can be pushed out through a much smaller pipe, rather than a larger SVP. This gives much more flexibility in where the toilet can be located and where the additional pipework can be run, because of its smaller size.

A single toilet macerator pump and tank typically cost around £150 – £300 and can work with most traditional toilets.

However, some things to consider about macerator toilets. The pump does add extra noise to your daily plumbing noises and requires an electrical connection. So you can’t use it in a power cut. You must be careful with what gets flushed down the loo as the macerator is not equipped to grind up anything more solid than human waste. Unclogging a macerator can be nasty work because it will require more than a plunger to clear the blockage.

Overall, if you really want a bathroom in your basement or the other side of the house to your SVP, a macerator toilet may fit the bill.

Do I Need Planning Permission To Add A Bathroom To My House?

According to UK Planning Regulations: ‘A planning application for installing a kitchen or bathroom is generally not required unless it is part of a house extension. However, if your property is a listed building you should consult the local planning authority.’ – UK Planning Portal

Remember that all electrical work must be conducted by a qualified electrician and that any work to boilers or heating systems must be carried out by a Gas Safe-compliant engineer.

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Final Thoughts…

There you have it! Advice and information on adding another bathroom anywhere in a house.

There are many reasons you might want to add another bathroom to your house, and it is always possible. However, the location (and how close it is to existing water and waste pipes) will be the biggest factor in determining how difficult and costly it will be to install.

Weigh up the cost and difficulty against the day-to-day benefits and potential house value increase to help make the best decision for you and your home.


Michael R

Michael is a KBB designer from the UK. He's been designing and project managing new Kitchen, Bedroom and Bathroom installations for over eight years now, and before that, he was an electrician and part of a KBB fitting team. He created The Bathroom Blueprint in early 2020.