Do You Need Planning Permission For A New Bathroom?
Luxury Bathrooms Exeter
The short answer is that replacing a bathroom in an existing room almost never needs planning permission, and usually does not need building regulations approval either. The longer answer is worth reading, because there are five specific situations that flip it, one very widespread myth that will make you spend money you do not need to spend, and a set of heritage constraints that catch out a surprising number of Exeter and East Devon homeowners.
We should say what this article is not. It is general guidance, not advice on your specific property, and if you are anywhere near a listed building the only safe route is to ask your local authority. What it will do is tell you which questions to ask and stop you being told something incorrect by somebody quoting for the work.
Planning permission and building regulations are two different things
People use the phrases interchangeably and they are unrelated regimes.
Planning permission is about the appearance and use of a building and its effect on its surroundings. It is broadly concerned with the outside. Refitting an existing bathroom is internal work and does not engage it.
Building regulations are about how the work is constructed - whether it is safe, drains properly, ventilates adequately and is electrically sound. They apply regardless of planning, and they are the ones that matter for a bathroom. The government’s own summary at GOV.UK’s building regulations approval page lists “install a bathroom that will involve plumbing” as work needing approval, which reads alarmingly until you understand the distinction it is drawing: a genuinely new bathroom with new plumbing needs approval, whereas replacing existing sanitaryware in the same positions does not.
That distinction is in Schedule 4 of the Building Regulations, which makes it non-notifiable to replace a WC, washbasin, sink, bidet, fixed bath or shower - provided the work does not involve underground drainage or changes to the water and hot water systems that could affect safety.
The five things that make it notifiable
Here is the practical list. If none of these apply, your bathroom project probably needs no approval at all.
A new electrical circuit, a replaced consumer unit, or altered circuits in the special location. More on the special location below, because this is where the myth lives.
Changes to below-ground drainage. Altering an underground drain or making a new connection is notifiable. Moving a soil stack or extending drainage to reach a new bathroom will often trigger this. There is a related consent too: if work goes over or within three metres of a public sewer or lateral drain, South West Water’s own build-over consent is needed, which is separate from building control.
Structural work. Removing or altering a load-bearing wall to enlarge the room brings Part A into play, and needs approval and usually a structural engineer’s calculations.
A new or replaced window. This engages ventilation, thermal and safety-glazing requirements, and is notifiable in its own right.
An unvented hot water storage system. Installing one is Part G3 work and sits within competent-person scheme territory.
That is the whole list. Everything else in a typical bathroom refit - new tiling, a new suite in the same positions, a new shower valve, replacing an extractor fan on existing cabling - is not notifiable.
The Part P myth, and why it costs people money
You will read, on a great many bathroom company websites, that all electrical work in a bathroom is notifiable - that even moving a light fitting or adding a shaver socket must be certified. This is not true in England and has not been since the 2013 edition of Approved Document P.
The regulation is specific. Notifiable work is the installation of a new circuit, the replacement of a consumer unit, or any addition or alteration to existing circuits in a special location. And the special location is defined tightly. Within a room containing a bath or shower, it is the space around the bath tap or shower head extending vertically from floor level to 2.25 metres - or to the shower head position if that is higher - and horizontally 0.6 metres from the edge of the bath or tray, or 1.2 metres from the shower head centre where there is no tray.
Approved Document P then says plainly, at paragraph 2.7, that all other electrical installation work is not notifiable: additions and alterations outside special locations, and replacements, repairs and maintenance anywhere. You can check this yourself in Approved Document P.
Two things follow. First, in a large bathroom, a light fitting on the far wall may well sit outside the envelope entirely. Second, and more usefully: a firm that repeats the myth is telling you it has not read the regulation it claims to work to. That is a genuinely helpful signal when you are choosing between quotes, and it is one of the questions in our guide to choosing a bathroom fitter in Exeter.
None of this means the electrical safety requirements go away. The BS 7671 zone rules apply throughout regardless of notification: IPX4 as a minimum in zones 1 and 2, 12V SELV only inside the shower basin, 30mA RCD protection on all circuits in the room, and a standard socket at least three metres horizontally from the zone 1 boundary. Notification and safety are separate questions.
The other myth: the 48 degree bath limit
There is a second widely repeated claim, and this one is about hot water.
Approved Document G does require that the hot water supply to a fixed bath incorporates measures ensuring the delivered temperature cannot exceed 48°C, achieved with an in-line blending valve fitted with a maximum temperature stop. That part is real.
What almost nobody mentions is the scope. The limits on application in the document state that the requirement applies only when a dwelling is erected, or is formed by a material change of use. In other words: new build and conversions. For a straightforward bathroom replacement in an existing Exeter home, the 48°C thermostatic blending valve is not legally required.
We fit them anyway and recommend them, particularly in households with young children or older residents, and the Chartered Institute of Plumbing and Heating Engineering runs a scalding-awareness campaign that makes the safety case properly. But there is a difference between recommending something as sensible and telling a customer it is a regulation they would be breaching. If a quote presents it as the latter, ask which regulation and read the limits on application.
Ventilation, and a provision that helps period properties
Approved Document F sets the numbers. A bathroom needs intermittent extract at 15 litres per second, or continuous extract at 8 litres per second. The fan must be positioned as high as practicable and no more than 400mm below the ceiling. Where a room has no openable window, the fan needs controls that keep it running for at least 15 minutes after the room is vacated. And where a wet room has no external walls at all, the guidance is four air changes per hour.
Then there is paragraph 3.31, which is the most useful sentence in the document for anyone with an older house. It says that if there was no ventilation system in the original room, it is not necessary to provide one in the refurbished room - although additional ventilation may be necessary if the refurbishment would otherwise make the building less compliant than it was before.
For a listed Georgian house in Topsham or a Regency terrace in Sidmouth, that is significant. It means refitting a bathroom does not automatically oblige you to cut a new opening through a protected elevation to satisfy building control. Paragraph 3.30 adds that where work is carried out in a bathroom, existing fans should be retained or replaced - and 3.32 confirms that replacing a fan using the existing cabling does not need to be notified.
Our own view is that you should install good extraction whenever it is possible to do so, because ventilation is what determines whether a bathroom still looks good in five years. But it is worth knowing what is required as against what is advisable.
What changes if the property is listed
This is where Exeter and East Devon differ from a lot of the country, and where the real risk sits.
Exeter has 20 conservation areas and over 1,800 listed buildings. Exeter City Council’s own guidance on what is protected is unambiguous: the entire building is listed, which includes all internal features, and fixed fixtures and fittings are protected - and modern additions are included in the listing too. So a bathroom rip-out in a listed building is not, in the eyes of the local authority, a like-for-like job.
The picture across the surrounding towns:
- Topsham was amalgamated into Exeter in 1966, so its planning authority is Exeter City Council, not East Devon District Council - a distinction some quotes get wrong. Its conservation area was designated in 1967 and it has a high proportion of listed buildings.
- Exmouth has three separate conservation areas containing 134 listed buildings, and its conservation area appraisal already identifies lost original fenestration and added dormers as harm to the area’s character.
- Sidmouth has a conservation area in three parts, plus two further separate areas at Bickwell Valley and Salcombe Regis.
- Budleigh Salterton, Honiton and Crediton all have conservation areas covering their centres. Mid Devon puts the consequences bluntly for Crediton: unauthorised works to a listed building are a criminal offence.
- Exminster is not obviously in a conservation area, but Devington Park - the former county asylum converted into 118 homes - is a listed building, so a refit inside one of those apartments needs consent.
One further note on all of the above. On 16 July 2026 the government confirmed a four-unitary model for Devon, abolishing every district council and Devon County Council, with the new authorities taking effect in April 2028. The councils named here are correct at the time of writing, but the contact you need will change.
Drainage, soil vents and the listed-elevation workaround
The commonest practical conflict between a bathroom design and a heritage constraint is the soil vent pipe.
Approved Document H requires a ventilating pipe open to outside air to finish at least 900mm above any opening into the building within three metres. On a principal elevation of a listed building, or a rear elevation with the slate-hung stairwells and bowed sashes that Exmouth’s conservation appraisal specifically records, that is frequently unacceptable to a conservation officer. Historic England’s own guidance on putting in a new bathroom advises reusing existing pipe and vent runs, avoiding cutting new holes in old walls, and keeping soil pipes off front elevations.
There is a compliant way around it. Approved Document H also permits ventilated discharge stacks to terminate inside a building when fitted with air admittance valves to BS EN 12380, provided they sit in adequately ventilated and accessible positions. That single provision is what makes a lot of otherwise impossible period-property bathrooms viable, and it is a good test of whether a firm has worked on listed buildings before.
The same document sets the trap requirements that constrain layout: a bath or shower needs a 40mm trap with a 50mm seal, a basin or bidet a 32mm trap with a 75mm seal. Branch length limits matter too - an unventilated basin branch is limited to roughly 1.7 metres at 32mm, extending to around 3 metres at 40mm, before ventilation is required. That is often what decides which wall a basin can go on, which is why we work the drainage out at design stage rather than on site. There is more on that in our bathroom renovation page.
If you are off the mains, adding a bathroom needs checking
One last item, and it is the one that catches people out most expensively in rural Mid and East Devon.
Properties on a septic tank or small treatment plant are governed by the Environment Agency’s general binding rules for small sewage discharges. Those rules cap a discharge to ground at two cubic metres a day, and - critically - they require the maximum daily volume to be recalculated when sewage volume increases, which explicitly includes property extensions.
Adding a second bathroom or an en-suite to a farmhouse outside Honiton or Crediton can genuinely push a system past its threshold. There is a further East Devon consideration: a discharge within groundwater Source Protection Zone 1 needs an Environment Agency permit rather than relying on the general rules at all. Those zones are real here, because the Otter Valley boreholes supply drinking water to over 200,000 people.
None of this is a reason not to add a bathroom. It is a reason to establish the position before the design is fixed, rather than after the money is spent.
Common questions
Do I need permission to move a bathroom to a different room?
Planning permission, no. Building regulations, very likely yes - a bathroom in a new location almost always means new drainage and new electrical circuits, both of which are notifiable. If it involves removing a wall, Part A applies too.
Does converting a bathroom into a wet room need approval?
Not planning permission, as it is internal work. Building regulations apply to the drainage, the ventilation and any electrical work inside the special location. If the property is listed, internal alterations can need Listed Building Consent regardless of building regulations.
What happens if work was done without approval?
It becomes a problem when you sell, because your buyer’s solicitor will ask for the certificates. A regularisation application can be made retrospectively for building regulations, though it is more expensive and more disruptive than doing it correctly first time. For unauthorised work to a listed building the position is far more serious - it is a criminal offence.
Who certifies the electrical work?
A registered electrician working under a competent person scheme can self-certify notifiable electrical work and issue the certificate, without a separate building control application. Keep that certificate: it is what proves the work was done properly when you come to sell.