Bathroom Lighting Design: Mirrors, IP Zones and Getting It Right
The bathroom is the only room in a house where lighting design and electrical safety are the same conversation.
Everywhere else, a badly chosen fixture gives you a badly lit room. In a bathroom, it can kill someone. The body's electrical resistance drops sharply when wet, and a fault current that would be a mild tingle in a dry hallway can be fatal to someone standing in a shower tray. That is why bathrooms are treated as special locations in the wiring regulations of nearly every developed country.
It is also the room where lighting quality gets judged hardest. This is where people look closely at their own faces, every day, in a mirror. A bathroom can be perfectly safe, perfectly compliant, and still be a room where nobody can shave properly or apply makeup that looks right outside the house.
Most bathrooms fail on that second count. And they fail for a reason that is entirely predictable once you know where the light is coming from.
First, a Word on Regulations
Bathroom electrical rules are local, and the differences are not small.
The UK and most of Europe use a zone system based on IP ratings, set out in the UK by BS 7671 Section 701. The United States uses something different: damp and wet location listings, under NEC Article 410.10(D). These are not two versions of the same thing. A fixture correct under one is not automatically correct under the other.
This guide explains both. But regulations change, local authorities add requirements, and the cost of getting it wrong is high.
Electrical work in a bathroom should be designed and carried out by a qualified electrician working to current local rules. Use this to specify and to ask better questions. Do not use it instead of that.
IP Ratings in Plain Terms
IP stands for Ingress Protection: two digits describing two different things.
The first digit covers solid objects, 0 to 6. In a bathroom it rarely matters. The second digit covers water, 0 to 8. That is the one that counts.
| Second digit | Protects against |
|---|---|
| 0 | Nothing |
| 1 | Water dripping straight down |
| 4 | Splashing from any direction |
| 5 | Low pressure jets from any direction |
| 6 | Powerful jets |
| 7 | Temporary immersion to 1 metre |
| 8 | Continuous immersion |
(Abridged. Digits 2 and 3 cover dripping and spraying at defined angles and rarely come up in bathroom specification.)
You will often see IPX4 or IPX7 with an X. The X is not a value. It means solid ingress was not tested or declared, and only the water rating applies. For bathroom purposes, IPX4 and IP44 mean the same thing where it matters.
IP44 = splash-proof. IP65 = protected against jets. Those two cover almost every decision.
Bathroom Zones: UK and Europe
BS 7671 Section 701 divides a room containing a bath or shower into zones. The closer to the water, the stricter the rule.
| Zone | Where it is | Minimum rating | Notes |
|---|---|---|---|
| Zone 0 | Inside the bath tub or shower tray | IPX7 | SELV only, 12V AC or 30V DC max. Transformer outside zones 0 to 2. No switches or sockets. |
| Zone 1 | Directly above the bath or shower, to 2.25m above finished floor, or the highest fixed shower head if higher | IPX4 | IPX5 where water jets are likely, such as body jet systems or spaces hosed for cleaning. No sockets. |
| Zone 2 | 0.6m horizontally past the zone 1 boundary, same height | IPX4 | No 13A sockets. Shaver units to BS EN 61558-2-5 permitted if clear of direct spray. |
| Outside zones | Everything beyond that | None required (IP20 compliant) | Specify IP44 anyway. |
Three things about this table that catch people out.
A washbasin does not create a zone. Zone 2 is measured from zone 1, which is measured from the bath or shower. In most bathrooms the basin and mirror sit inside zone 2 anyway, but that is the layout doing it, not a rule about basins.
Outside the zones, IP20 is legal but unwise. Steam fills the whole room regardless of where boundaries fall. IP44 throughout costs very little and removes the question entirely.
Wet rooms are stricter, not looser. Where a shower has no tray, basin or enclosure: there is no zone 2 at all, zone 1 extends 1.2m horizontally from the centre of the fixed shower head, and zone 0 becomes the floor up to 100mm across that same extent. The absence of a tray makes the zones bigger.
There Is No Zone 3
A lot of bathroom lighting guidance still refers to a zone 3, including articles written this year.
Zone 3 was removed from BS 7671 in the 17th Edition in 2008. Those areas are now simply outside the zones.
If a supplier, data sheet or guide is telling you about zone 3, it is working from rules superseded more than fifteen years ago. Treat the rest of its compliance advice the same way.
RCD Protection
Every circuit serving a room with a bath or shower needs 30mA RCD protection under Regulation 701.411.3.3. The only exception is SELV. This applies equally to circuits that merely pass through zone 1 or zone 2 on the way somewhere else.
RCD requirements in the UK have been broadening across recent amendment cycles, with more domestic lighting circuits pulled into scope. Because amendments arrive regularly, confirm what currently applies with your electrician rather than relying on any published summary, this one included.
Under Amendment 2, supplementary bonding is no longer required in a bathroom where RCD protection and main protective bonding are both present.
The United States Works Differently
The NEC does not use IP zones. It uses damp location and wet location listings, plus a restricted zone where certain fixture types are banned outright regardless of rating.
NEC 410.10(D) sets two rules:
One. No cord-connected luminaires, chain, cable or cord-suspended luminaires, lighting track, pendants, or ceiling-suspended paddle fans may have any part inside a zone of 3 feet (900mm) horizontally and 8 feet (2.5m) vertically from the top of the bath rim or shower threshold. This includes the space directly above the tub. A wet location listing does not exempt a fixture from this.
Two. Luminaires within the outside dimension of the tub or shower, up to 8 feet above the rim, must be marked suitable for damp locations, or suitable for wet locations if subject to shower spray.
The 2023 edition confirmed that a ceiling fan supplied with a light kit counts as a luminaire here.
What this means in practice: the pendant over a freestanding bath, a staple of contemporary bathroom photography, is non-compliant in the US if any part sits inside that zone. In the UK the same pendant may be fine with the right IP rating. This is the clearest example of why bathroom imagery does not travel between markets.
The Mirror: Where Most Bathrooms Fail
Everything above decides what is safe. This decides whether the room works, and it is where most bathrooms, including expensive ones, go wrong.
Why Overhead Light Fails
Light travels in straight lines.
When the only light at a vanity comes from above the mirror or from the ceiling in front of it, it reaches the face at a steep downward angle. The brow, the nose and the chin each block it and cast a shadow straight down.
The result is always the same: dark eye sockets, a shadow under the nose, a hard line under the jaw. It exaggerates every contour and hides exactly what people are trying to see.
This is not a brightness problem. Adding lumens to an overhead source makes the shadows harder, not softer. The angle is the problem.
Cross-Illumination Is the Fix
Put two sources either side of the mirror at roughly face height, so the beams cross in front of the face.
Light from the left fills the shadow cast from the right, and the reverse. The face is lit evenly from the front, and contours read accurately instead of being exaggerated.
This is the same principle used in film and photography, and it is why theatre dressing room mirrors have been ringed with bulbs for over a century rather than lit from above. It is geometry, not taste.
The Measurements
| What | Specification |
|---|---|
| Sconce height, centre of fixture | 152 to 168cm (60 to 66 in) from finished floor |
| Sconce spacing, centre to centre | 71 to 91cm (28 to 36 in) |
| Clearance from mirror edge | 5 to 15cm (2 to 6 in) |
| Above-mirror bar height, centre | 190 to 203cm (75 to 80 in) from floor |
| Above-mirror bar width | 60 to 80 percent of mirror width |
| Vertical illuminance at face | 300 to 500 lux |
On wide vanities, past about 180cm or on a double basin, a pair of sconces cannot cover the span evenly. Add a third centred fixture, or treat each mirror separately with its own pair.
Always diffuse. A bare lamp at eye level glares straight into the user's eyes and into the mirror. Frosted glass, opal diffusers or shades.
When Side Sconces Will Not Fit
Wall space is not always available, especially in narrow bathrooms or where the mirror spans the full vanity.
An illuminated mirror is the better fallback. Light comes from the plane of the glass at face height, so it lights the face frontally without needing wall space. Specify CRI 90 or above, ideally with dimming and tunable colour temperature. Backlit halo mirrors are softer than edge-lit panels but put less light on the face.
An above-mirror bar is the last resort. Even specified correctly, it will cast more facial shadow than side lighting. Choose one that diffuses downward and outward rather than throwing a narrow beam straight down.
Best of all: an illuminated mirror plus side sconces. The mirror gives diffuse frontal fill, the sconces give directional cross-light.
Measure Vertically, Not Horizontally
This gets missed almost everywhere.
Most lighting specs state illuminance horizontally, measured on a flat surface like a countertop. At a mirror that is the wrong measurement, because nobody's face is horizontal.
A bathroom can hit its horizontal target on the counter and still leave faces in shadow. The room gets signed off and is still no good for grooming.
The Four Layers
1. Ambient. General light for moving around safely, usually recessed downlights rated for whichever zone they sit in. Target roughly 150 to 200 lux. Domestic lighting has no legally mandated levels, so treat this as established design practice rather than a regulated figure.
Position downlights to wash the walls rather than in a grid down the ceiling centre. Light on vertical surfaces makes a bathroom feel bigger and brighter than the same output aimed at the floor. Never put a downlight directly in front of the mirror. It produces exactly the top-down shadow the vanity lighting exists to eliminate.
2. Task. Mirror and vanity lighting, covered above. This layer decides whether the room functions.
3. Accent. What separates a functional bathroom from a considered one: shower niche lighting (needs the right IP rating for zone 1), under-vanity or plinth lighting that floats the joinery, wall grazing on tile or stone worth revealing, or a backlit mirror halo working independently of its task role.
4. Night lighting. Worth designing rather than ignoring. Bathrooms get used at night, and a full scene at 3am delivers a dose of light that suppresses melatonin and makes getting back to sleep harder. A separate low level circuit solves it, from plinth lighting, a step light or a dimmed mirror halo. Somewhere around 10 to 20 lux works well, though that is a design judgment rather than a standards figure.
Colour Temperature and CRI
CCT: A Real Disagreement
Published guidance ranges from 2700K to 6000K. The disagreement is genuine, because both sides have a point.
For warm (2700K to 3000K): flattering, renders skin softly, consistent with the rest of the house, suits an evening bath.
For cooler (3500K to 5000K): makeup applied under warm light looks different outdoors, because it was applied under light biased toward red. Closer to daylight gives a result that transfers.
The practical answer: 3000K for most homes. Warm enough not to feel clinical, neutral enough for accurate grooming. Above 4000K a bathroom starts reading as a public washroom.
Where makeup accuracy really matters, use tunable white at the mirror only, roughly 2700K to 4000K, with the ambient layer fixed at 3000K. That gives a daylight-referenced setting for grooming and a warm one for the evening, in the same room.
Never mix fixed colour temperatures across circuits. A 3000K ambient layer beside a 4000K vanity light produces a visible line where they meet.
CRI Matters More Than CCT Here
This is the cheapest meaningful upgrade available in a bathroom.
Specify CRI 90 minimum, CRI 95 where you can. People examine their own skin closely in a bathroom. Low CRI renders skin badly whatever the colour temperature, and it registers as looking tired without anyone knowing why.
Check the R9 value as well as headline CRI. R9 covers deep red rendering specifically, and skin tone accuracy leans heavily on it. Two sources both rated CRI 90 can differ substantially. Aim for R9 above 50 at the vanity.
Seven Mistakes That Ruin Bathrooms
1. Lighting the vanity from above only. The defining error. More brightness makes it worse. Side lighting at face height is the fix.
2. Sconces at the wrong height. At eye level they work. High near the top of the mirror, you are back to the overhead problem. Low, they glare. 152 to 168cm to the centre, measured rather than eyeballed.
3. Specifying to zone 3. It does not exist and has not since 2008.
4. Assuming a wet room has smaller zones. It has larger ones.
5. IP20 outside the zones. Compliant but unwise. Steam fills the whole room.
6. No dimming and no night circuit. A bathroom at 7am and at 3am need different things.
7. Specifying horizontal lux only. The room passes on paper and leaves faces in shadow.
Frequently Asked Questions
What IP rating do bathroom lights need? It depends on the zone. Under BS 7671 Section 701: zone 0 (inside the bath or shower tray) needs IPX7 and SELV at 12V AC maximum. Zone 1 (above the bath or shower to 2.25m) needs IPX4, or IPX5 where water jets are likely. Zone 2 (0.6m past zone 1) needs IPX4. Outside the zones there is no requirement and IP20 is compliant, but IP44 throughout is the sensible specification because steam reaches the whole room. The United States uses a different framework entirely, based on damp and wet location listings under NEC 410.10(D).
Is there a zone 3 in a bathroom? No. Zone 3 was removed from BS 7671 in the 17th Edition in 2008, and those areas are now simply outside the zones. Plenty of published guidance still refers to it, including recent articles. If a source describes zone 3 requirements, it is working from rules superseded more than fifteen years ago, and its other compliance advice deserves the same scepticism.
Should vanity lights go above the mirror or on the sides? On the sides, wherever wall space allows. Light from above reaches the face at a steep downward angle, and the brow, nose and chin each cast a shadow beneath themselves, giving dark eye sockets and a hard jaw line. Two sources either side at face height produce cross-illumination, where each beam fills the shadow the other casts, giving even frontal light and an accurate reflection. It is the same reason theatre dressing room mirrors are ringed with bulbs. Where side mounting is impossible, an illuminated mirror is the better fallback and an above-mirror bar the last resort.
How high should bathroom vanity sconces be? Centre of each fixture at 152 to 168cm (60 to 66 inches) from the finished floor, roughly eye level for most adults. Space them 71 to 91cm (28 to 36 inches) apart, each 5 to 15cm (2 to 6 inches) clear of the mirror edge. On vanities wider than about 180cm, or double basins, add a third centred fixture or treat each mirror separately. Always specify diffused fixtures, because a bare lamp at eye level glares into both the user's eyes and the mirror.
How high should an above-mirror light bar be? Centre of the fixture at 190 to 203cm (75 to 80 inches) from the floor, or 8 to 25cm (3 to 10 inches) above the top edge of the mirror. Size it at 60 to 80 percent of the mirror width, since an undersized bar leaves the outer edges dark. Pick a fixture that diffuses downward and outward rather than throwing a narrow beam straight down. Even specified well it will cast more facial shadow than side sconces, so pair it with a lit mirror where you can.
What lux level does a bathroom need? General ambient around 150 to 200 lux, which is established design practice rather than a regulated figure, since domestic lighting has no mandated levels. At the mirror, aim for 300 to 500 lux measured vertically at face height, not horizontally at the counter. That distinction matters: a bathroom can meet a horizontal target on the countertop and still leave faces in shadow, because a face is a vertical surface. A separate night circuit at a low level, somewhere around 10 to 20 lux, is worth adding.
What colour temperature is best for bathroom lighting? 3000K for most homes: warm enough to feel domestic, neutral enough for accurate grooming. Guidance genuinely conflicts here, because warmer light at 2700K flatters while cooler light closer to daylight gives makeup results that transfer better outdoors. Where that accuracy matters, specify tunable white at the mirror only, roughly 2700K to 4000K, with the ambient layer fixed at 3000K. Avoid fixed temperatures above 4000K in a home bathroom, and never mix fixed CCTs across circuits in one room.
What CRI should bathroom lighting have? CRI 90 minimum, CRI 95 where budget allows. People examine their own skin closely in a bathroom, and low CRI sources render skin tones badly regardless of colour temperature. Check the R9 value alongside headline CRI, since R9 covers deep red rendering and skin tone accuracy depends heavily on it. Two sources both rated CRI 90 can differ a lot. Aim for R9 above 50 at the vanity.
Can I hang a pendant over a bath? It depends entirely on where you are. In the United States, NEC 410.10(D) prohibits it if any part falls within 3 feet horizontally and 8 feet vertically of the bath rim or shower threshold, and a wet location listing does not exempt it. In the UK, a pendant may be acceptable with the right IP rating for its zone, which above a bath means IPX4 minimum in zone 1. This is the clearest case where bathroom design imagery does not transfer between markets, and it should be confirmed with a qualified electrician before you specify anything.
Do bathroom lights need RCD or GFCI protection? In the UK, yes, without exception. Regulation 701.411.3.3 of BS 7671 requires 30mA RCD protection on every circuit serving a room with a bath or shower, and on any circuit merely passing through zone 1 or zone 2. RCD requirements have been broadening across recent amendment cycles, so confirm what currently applies with your electrician. In the United States, GFCI requirements come from the NEC and vary by edition and local amendment, with some jurisdictions adding rules beyond the national code. Either way, this is a question for a qualified electrician working to current local requirements.