Bathroom zones: what do they mean for your bathroom refit?

What are the bathroom zones, in plain terms?

They are measured from the bath or shower, not from the walls of the room. BS 7671, the wiring regulations, defines them in its section on locations containing a bath or shower.

• Zone 0 is the inside of the bath or shower tray, the place that actually fills with water.
• Zone 1 is the space directly above the bath or tray, up to 2.25 metres from the floor. For a walk-in shower with no tray, it spreads out from the fixed shower head rather than stopping at an edge.
• Zone 2 is a band 0.6 metres wide around zone 1, also up to 2.25 metres high.
• Outside the zones is everything else. There used to be a zone 3, but it was removed from the regulations years ago and outside the zones the normal rules apply, with RCD protection.

The honest shorthand: the closer to where water lands, the less can go there and the better sealed it has to be.

What can go in each zone?

Less than people expect in zones 0 and 1, and more than people expect outside them.

• Zone 0 takes almost nothing: only equipment made for it, at extra low voltage, and rated to be submerged.
• Zone 1 takes fixed equipment made for the position, such as an electric shower, a shower pump or a sealed downlight over the bath. Equipment here must be rated at least IPX4, meaning protected against splashing from any direction, and higher where jets are used to clean.
• Zone 2 takes the same, plus things like a heated towel rail, a lit mirror or an extractor fan, again at IPX4 or better, and a shaver supply unit out of the way of direct spray.
• Outside the zones is where switches and anything with a plug belong. Electrical Safety First points out that a ceiling pull cord switch is a better option than an ordinary wall switch in a bathroom, because of damp and wet hands.

An electric shower must be installed by a registered competent electrician and supplied on its own circuit, which is Electrical Safety First’s wording rather than ours, and it is usually the biggest single item in a bathroom’s electrics.

Can I have a plug socket in the bathroom?

Only if it can sit at least 2.5 metres from the edge of the bath or shower tray, which in most British bathrooms it cannot.

Electrical Safety First states that sockets are not allowed in bathrooms or shower rooms, apart from shaver supply units, unless they can be fitted at least 2.5 metres from zone 1. A shaver point is the exception because it is built to a separate standard with an isolating transformer. Anything needing a normal plug, a hairdryer or straighteners, belongs on a socket outside the room.

Does everything in a bathroom need RCD protection?

Yes. Every circuit in or passing through a bathroom or shower room needs RCD protection.

That includes the lighting, the shower, the fan and the underfloor heating, and a circuit that simply runs through the room on its way somewhere else. If your board has no RCDs, a bathroom refit is often the moment it gets looked at, which our fuse board replacement article walks through.

The related question is supplementary bonding, the green and yellow earth cables clipped to pipes in older bathrooms. Under current regulations it can often be left out of a refit, but only when every circuit is RCD protected and the main bonding at the incoming services is sound. That is something to test, not assume.

What should be decided before the bathroom fitter starts?

The layout, because the layout sets the zones, and the zones set the electrics.

Here is the thing a sales-led quote will not print. Moving the shower moves the zones. A light, a fan or a towel rail that was fine where it sat can end up in the wrong zone once the bath swaps to a walk-in shower on the opposite wall. We see refits where the plumbing and tiling were done beautifully and the electrics were simply left where they were.

So agree these with the fitter before first fix, while the walls and floor are open: where the shower and bath go, the lights and their ratings, the fan and its duct route, the towel rail, the mirror, underfloor heating and its thermostat, the shaver point, and where the switches and pull cord sit. Our kitchen refit article covers the same handover with a kitchen fitter.

Is bathroom electrical work notifiable?

In England, yes, for most of it. Adding to or altering a circuit in a room with a bath or shower is notifiable, and so is any new circuit. That is the opposite of a kitchen, which stopped being a special location in 2013.

It means the work is done by an electrician registered on a competent person scheme, or it goes through building control. As an NICEIC Approved Contractor we test the work, issue the certificate and notify building control ourselves. Swapping a like for like light fitting or fan in the same place is not notifiable, but it still has to be rated for its zone. Wales kept its own, stricter rules.

What changes the price of the electrics in a bathroom refit?

We price the electrics once we know the layout, because the layout is most of the answer.

• Whether the shower is electric, and whether the existing cable and board can support it.
• Whether the shower or bath is moving, and therefore how much has to move with it.
• Lighting, fan, towel rail, mirror and underfloor heating, and how many of each.
• Whether the consumer unit already gives RCD protection.
• Whether the room is stripped back to brick or walls stay and have to be made good.

Send us the bathroom plan through our quote page. Our kitchen and bathroom electrics page explains how we work alongside a fitter.

Questions we get asked about this