Guide to bathroom building regulations

A new bathroom is a great asset to any home, but before you refurbish yours, it’s important to know about the relevant building regulations – find out more here.

bathroom building regulations

Make sure your new bathroom complies
with UK building regulations

The bathroom is one of the most used rooms in the home so it needs to be functional, warm and easy to clean as well as attractive. Before you begin to plan a new bathroom refurbishment though, you need to make sure your plans meet current UK building regulations which are designed to ensure the health, safety and comfort of all homes. Here’s a guide to the relevant building regulations for bathroom refurbishment:

Part H – Drainage and waste disposal

It’s essential that your bathroom plumbing is installed correctly for safety and hygiene reasons, so hire a qualified plumber for this work. They will adhere to building regulations, which include making sure waste pipes and drainage run downhill from the appliance to the outlet – if this isn’t the case, such as in a basement conversion, you will need to install a pump system like a Saniflow. The Water Regulations Advisory Scheme also applies to bathroom plumbing; the regulations were devised to prevent water wastage, misuse and contamination.

Part F – Ventilation

Ventilation is especially important in moist areas like kitchens and bathrooms to prevent damp and mould, which can be harmful to properties as well as health. Building regulations state that bathrooms must be ventilated via a window or extractor fan – you may want to use both. A new bathroom should have a fan which extracts at a rate of at least 15 litres per minute and continues to run for 15 minutes after the light has been switched off.

Part P – Electrical safety

Water and faulty electrics can be a lethal combination, which is why it’s illegal to carry out electrical work in the bathroom unless you are a qualified electrician registered with an approved scheme like the Electrical Contractors’ Association (ECA) or the National Inspection Council for Electrical Installation Contracting (NICEIC). Part P ensures that all household electrics are installed safely; rules for bathroom electrics for example specify the maximum voltage levels for different areas in the bathroom and state that light switches should be pull chord operated or located outside the bathroom.

Part A – Structural safety

It’s necessary to look at the structural safety of your bathroom, especially if you are extensively refurbishing or building a new room from scratch. You would need to make sure, for instance, that the floor is structurally secure enough to hold your bathroom suite and a full bathtub.

If you are unsure about whether your bathroom refurbishment complies with UK building regulations, always seek advice from a professional bathroom installation company. Make sure that you ask for references and insurance credentials from all contractors before you hire and get at least three quotes for the work. If you want more inspiration on bathroom design, take a look at our expert tips here.

Steven Russell says:

Hi. I live in social housing. The flat is old, at least 60 years old. I have been told that the bathroom was given a new suite in 1995. The bath tub is 150 mil, so smaller than a standard bath,the bath tub panels have been from hard board and edged with aluminium with sharp edges, from the centre line of the toilet to the edge of the bath there is only 11.5 inches, from the front of the toilet to the front edge of the sink is a space of 17 inches, the bathroom door is 26.5 inches,there is a cupboard that used to house the water tank (this has now been removed), the cupboard door opens into the bathroom door opening space.
I know that regulations often change and a social landlord is not required to implement changes immediately, but when a bathroom is due for renewal the latest building regulations apply. As my bathroom was apparently changed in 1995 does it conform to the most current building regulations of the time?

mjackson says:

Hi Steven,

We recommend taking a look at the Repairs, planning and building regulations website which will give you information on your tenants rights.

We also advise discussing any queries with your social landlord who should have information on their legal obligations to their tenants.

We hope that this information helps.


phil says:

hi , i live in a property which a lease hold, it was built approx 6yrs ago, the bathroom has no window, no fresh air no daylight, also it is straight off the kitchen no passageway between the kitchen, just one door, does this follow building regs?, also i asked permission to have a window fitted in the bathroom at my expense, i was not given permission, can i appeal.

mjackson says:

Hi Phil,

Thanks for your post.

We recommend taking a look at the planning portal website where you will find further information in regards to UK building regulations.

We hope that this information helps.

Mark @ Servicemagic

R Lucas says:

I live in a end terrace next door has fixed a fan no timer he leaves it running for hours it is also fixed next to the party wall which is very loud is there any regs to state it must b with in a certain distance from the wall I have spoke to him but he tells me to live with it

mjackson says:


Thanks for your post.

We would recommend searching for your local environmental health office (the council will be able to point you in the right direction) in order to report the noise you are experiencing.

They will then advise on the options you have available.

We hope this helps.

Mark @ Servicemagic

Michael says:

Is it best practice to fit shut of valves on the bath toilet and sink when installing in a refurb end bathroom?

mjackson says:

Hi Michael,

We have done some research on this and it seems as if it would be safer to install shut off valves on every hot and cold water supply pipe this will allow you to shut off the water to one sink without disrupting the flow to others but they’ll also provide a quick way to turn off the water in the event of a flood caused by, for instance, a cracked fitting or ruptured supply pipe.

A professional plumber would be the best person to speak to however, we do hope that this information helps.

Mark @ Servicemagic

Grace says:

Hi, I’ve just bought a New Build property a few months ago and was wondering if the light fitting in my bathroom is legal.
They have fitted a bayonet light with an energy efficient bulb. There is no bathroom shade on the light and it looks like the same fitting which is in my kitchen. The more worrying thing is that it’s just above the shower and I was wondering if the developer is responsible for safety or is it on my hands to make sure there is a sealed shade on the light?

mjackson says:

Hi Grace,

You need to check whether your bathroom light fitting has an ”IP Rating” (International Protection Marking) ..

Your property manager should be able to confirm this or arrange for an electrician to come and check if they aren’t sure.

It is very important that you get this checked right away as any light fittings in the bathroom that aren’t IP rated would be unsafe and potentially illegal.

I hope that this information helps.

Mark @ Servicemagic

Helen Wilkes says:

Hi, I am having a new wet room/shower room converted from part of my garage. Are there any regulations stopping me from putting the boiler in there, and what about a washing machine? I am hoping to have a small window plus and extractor fan. The room will be 2360 x 1704.

mjackson says:

Hi Helen,

Thanks for your post.

It is possible to have the boiler situated in the garage however there are regulations that would need to be met.

The best thing would be to organise a site visit where a professional can come out and carry out an assessment for you.

You can also request up to 4 free quotes on the work by completing our online request form.

Mark @ Servicemagic

Julien says:

I was wondering if it was an obligation to have an unvented cylinder if you put 3 bathroom in a house?
Thank you. Julien

mjackson says:

Hi Julien,
It would be hard for us to say as we aren’t professionals therefore, we would suggest speaking to your local councils building regulation department who maybe able to advise further.

Andrew Blight says:

Are there any regulations in terms of plastering when refitting a bathroom? Should there be any special waterproofing that is part of plastering or is it the same as for any other room?

Thanks Andrew

mjackson says:

Hi Andrew
As we aren’t professional plasterers, it would be hard for us to say however an online search for plastering regulations should point you in the right direction.
You can also try and contact your local building regulations office who may also be able to advise.

lanette says:

hi i wonder if anyone can help me, in my rented accommodation i have noticed that the tiles on the bathroom floor run down to the bathroom floor and into the kitchen, so basically wall tiles are floor tiles, however any water drip/spills you go flying same if you ware certain shoes, is this illegal? is there any site or persons i can call? this is not the start of issues but one i cannot find solid info on

help really needed


mjackson says:

Hi Lanette,

Thanks for your post.

It’s quite a complicated subject, that we have very little knowledge on therefore, would that you contact your landlord and tell them of your concerns.

They may consider laying new flooring should tenants safety be at risk.

You can also contact the health and safety executive who should be able to advise.

Thanks again

Colin Williams says:

I have a bathroom floor which comprises approximately 19 mm particleboard with 6 mm plywood tacked on top. I have been told that if I want to put ceramic tiles on the floor I need to use a flexible adhesive (for flexibility so tiles don’t crack) this I understand, but I’ve also been told I need to either change the plywood for 15 mil plywood or 6 mm cement backer board.

Now as 15 mil plywood would raise the floor excessively, I will probably just get the backer board.

My question therefore is; is the above correct or can I just PVA over the 6mm plywood then use a flexible adhesive?

Floor area approx 200 cm x 140 cm.

Many thanks in advance.


mjackson says:

Hi Colin,

Thanks for your post.

As we are not experts in this field it would be hard for us to advise.

We would recommend searching online, for local contractors who might be able to advise.

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