What qualified trades do you legally need for a bathroom fit? Part P and Gas Safe explained

A bathroom is one of the few rooms in a UK home where the law is quite specific about who's allowed to do certain kinds of work, mainly because water and electricity in close proximity carry genuine safety risk. Two separate legal frameworks come into play for most bathroom fits — Part P of the Building Regulations for electrical work, and Gas Safe registration for any gas work — and it's worth understanding both before assuming any competent tradesperson can simply get on with everything.

Part P treats a bathroom or shower room as a "special location," with defined zones around the bath or shower where stricter rules apply to what electrical equipment can be installed and how it must be protected. In practice, this means electrical work in a bathroom beyond simple like-for-like replacement of an existing accessory on an existing circuit is generally notifiable under Building Regulations — this commonly includes installing a new shower circuit, wiring for a new electric towel rail, new extractor fan wiring, new lighting circuits, or a new shaver socket. Notifiable work has to go through one of two routes: either it's carried out by an electrician registered with a competent person scheme such as NICEIC or NAPIT, who can self-certify the work as compliant, or it's notified to the local authority's Building Control department directly, who inspect and sign it off. Using an unregistered electrician for notifiable bathroom work, or having no Building Control involvement at all, leaves the work uncertified — a problem that can surface later when selling the property or in the event of an insurance claim following an electrical fault.

Gas Safe registration works differently but is equally non-negotiable wherever it applies. Any work installing, repairing, servicing, or even adjusting a gas appliance — most relevantly for a bathroom refit, moving a combi boiler to a different location, or fitting a gas-fired heated towel rail — is a legal requirement to be carried out only by an engineer on the Gas Safe Register, under the Gas Safety (Installation and Use) Regulations. This isn't a recommendation or a quality mark; it's the law, and using someone who isn't Gas Safe registered for this kind of work is a genuine legal and safety issue, not simply a matter of preference. There are also specific restrictions on siting gas appliances in bathrooms: a gas appliance should generally only be installed in a room containing a bath or shower if there's genuinely no other practical location for it, it needs to be a room-sealed appliance kept away from sources of water, and any electrical switches or fittings within reach of the bath or shower zones need appropriate waterproof-rated protection along with a residual current device (RCD) rated at no more than 30 milliamps.

Alongside electrics and gas, Part G of the Building Regulations covers hot water safety and water efficiency, and it's worth being aware of even though it doesn't require a specific registered trade in the same way. Part G commonly requires hot water supplied to a bath to be limited to a safe temperature, generally cited around 48°C, typically achieved with a thermostatic mixing valve, since water at higher temperatures can cause a serious burn within seconds — a real safety consideration in households with young children or elderly or vulnerable residents. Part G also sets a water efficiency standard for new work, commonly cited as 125 litres per person per day, with a tighter optional standard of 110 litres per person per day used in some water-stressed areas, generally met through fittings like aerated taps, dual-flush toilets and low-flow showerheads.

Practically, the safest approach when planning a bathroom fit is to ask directly, before work starts, which parts of the job are notifiable under Part P, who's actually going to carry out and certify that work, and — separately — whether any part of the job involves gas work and, if so, to see the individual's Gas Safe registration card and ID number, which can be checked directly against the Gas Safe Register. A reputable fitter or builder should be entirely comfortable answering these questions and, in most cases, will already have a registered electrician and, where relevant, a Gas Safe engineer as part of their usual working setup rather than needing to be pushed on the point.

Frequently asked questions