An electrical fire linked to a hot tub or sauna with no valid inspection certificate is one of the fastest ways to turn a single bad night into a voided insurance claim. Insurers routinely decline fire and liability claims where a holiday let owner cannot produce an up-to-date Electrical Installation Condition Report for the circuit involved, and a hot tub sitting on a domestic ring main with no dedicated RCD protection is exactly the kind of installation that fails that test. The guest injury or property damage still has to be paid for. It just will not be your insurer paying for it.
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Hot tubs and saunas are two of the most requested add-ons in the UK holiday let market, and two of the easiest features to get wrong on fire and electrical safety. Neither sits inside the Electrical Safety Standards in the Private Rented Sector (England) Regulations 2020, because those regulations only bite on assured shorthold and similar tenancies, not genuine short-term holiday accommodation. That does not mean you are off the hook. You still owe guests a duty of care under the Occupiers' Liability Act 1957, and your fire risk assessment under the Regulatory Reform (Fire Safety) Order 2005 has to account for both installations properly, in writing, since the Building Safety Act 2022 closed off the old exemption for smaller premises in October 2023.
Hot tubs: water, electricity and why the wiring rules are strict
A hot tub combines mains electricity with a large volume of water guests are sitting in, which is precisely the scenario BS 7671 (the IET Wiring Regulations) singles out for extra protection under its Part 7 special locations rules. In practice that means supplementary equipotential bonding, correctly rated cable and isolation, and RCD protection on the circuit: 30mA RCD protection is required on outdoor circuits generally, and a hot tub supply needs its own fixed RCD at the consumer unit rather than relying on a shared circuit somewhere else in the property.
The electrical work to install a hot tub supply is notifiable under Part P of the Building Regulations, meaning it has to go through a competent-person scheme electrician or be signed off by building control. Once it is in, do not treat that as a one-off job finished forever. Hot tubs sit outdoors, exposed to weather and constant use across a season of changeovers, and an annual check by a qualified electrician is the standard recommendation for keeping RCD protection and connections in good working order.
The faults that actually start fires
Most hot tub electrical fires trace back to a small number of recurring faults rather than anything exotic. A cracked or degraded GRP shell lets water track down into the pump housing and control box over months, corroding connections until something arcs. Undersized or damaged cable buried too shallow, or run through a garden with strimmers and spades nearby, is another repeat offender. So is a control box mounted where rain and condensation can pool inside it despite the IP rating on the label. None of these show up on a visual glance from the deck. They show up on the annual inspection, which is the whole argument for actually booking one rather than treating it as optional because the tub "seems fine."
What a missing certificate costs you
Ask your insurer directly whether your policy is written for a short-term let with a hot tub, because plenty of standard holiday home policies carry exclusions or extra conditions around hot tubs and pools that owners do not spot until a claim gets refused. If a fire, shock or scald incident happens and you cannot show a valid EICR for the relevant circuit, expect the claim to be challenged on the basis the installation was not properly maintained. That is a conversation worth having with your broker before the first booking goes out, not after an incident.
Saunas: the heater is the whole risk
An electric sauna heater needs the clearance to combustible timber walls and benches specified by its manufacturer, a steel or stone guard fitted over the element at all times, and installation and maintenance carried out by a qualified electrician working to the heater's own specification rather than a rough guess. Ground fault protection on the circuit matters here just as much as it does for a hot tub, given the mix of heat, timber and, often, a wet changing area right next door. Never let a guest or cleaner use the cabin with the guard removed or damaged, and put that check into your changeover routine rather than treating it as a once-a-season job.
Wood-fired sauna heaters bring a different set of problems. These fall under Building Regulations Part J for solid fuel combustion appliances, which means a properly specified flue and chimney system, adequate air supply for combustion, safe discharge of exhaust gases, and correct clearances between the hot flue and any combustible structure or hearth. Get the flue installation checked by someone competent to do so, and treat the annual sweep the same way you would a wood burner in the main cottage.
Smoke control areas catch wood-fired saunas out
Before installing a wood-fired sauna stove, check whether the property sits in a smoke control area. Most local authorities operate them, and inside one you can only burn an authorised fuel or use a stove on the DEFRA exempt appliances list, and most wood-fired sauna heaters are not on that list. Buying and fitting one anyway before checking is a common and entirely avoidable mistake, and it can leave you with a heater you are not legally allowed to use.
Fit a carbon monoxide alarm to BS EN 50291 near any wood-fired sauna heater regardless of exactly how the statutory alarm regulations apply to your particular letting arrangement. It is cheap, it is standard practice across the guidance written for paying-guest accommodation, and it closes off one of the more serious risks a solid fuel appliance in a small timber cabin creates.
Where this sits in your fire risk assessment
Both features need a named entry in your written fire risk assessment, not a passing mention. Record the installation date, who carried it out, the certification held (EICR, Part P completion certificate, gas or solid fuel safety check where relevant), and the date of your last annual inspection. Note where the isolation switch is for the hot tub and how a guest or member of staff would cut power to it in an emergency, and do the same for the sauna heater's isolator. If either sits in an outbuilding away from the main property, check that smoke and, where a wood-fired heater is involved, carbon monoxide alarms are fitted there too. Our guide to holiday let smoke and CO alarm requirements covers exactly which rooms need which alarm, and if the main cottage also has a wood burner or open fire, our piece on wood burners and open fires in holiday lets is worth reading alongside this one.
Changeover day is also when these features get missed. A quick visual check of the hot tub cover, the isolation switch, the sauna guard and the surrounding floor for scorch marks or damage takes a couple of minutes and belongs on the same checklist as testing your smoke alarms. If you have not written that checklist down yet, our complete holiday let fire risk assessment guide sets out what a thorough one should include.
Next steps
Hot tubs and saunas are exactly the kind of premium feature that gets guests to book, and exactly the kind of installation an insurer will scrutinise hardest after a claim. Get the EICR and Part P paperwork in a folder, confirm your policy actually covers what you have installed, and get both features written into your fire risk assessment properly rather than added as an afterthought.
FRASafe's holiday let fire risk assessment walks you through every area required by HMSO guidance, including outbuildings, hot tubs and sauna installations, completed online in 30 to 45 minutes for £45.