Installing your hot tub step by step: slab, electricity, filling

Step 1: approve the site

Everything starts with choosing the spot. The criteria to meet:

• a base that can carry the filled hot tub, flat and level;
• a power supply at a reasonable distance from the fuse board;
• a water point nearby for filling, and somewhere to drain the water;
• access to the hot tub's technical panel, for maintenance;
• some privacy and shelter: wind, overlooking neighbours, trees that shed their leaves.

Our guide Where to install your hot tub covers these points for every site: garden, deck, balcony, indoors or sunken. In a block of flats, or if you are planning a shelter or major landscaping, check the rules before ordering (building regulations, local authority).

Step 2: prepare the base

The concrete slab

This is the safest solution outdoors. It must be flat, level and slightly larger than the hot tub. Its design depends on the total weight: empty weight, plus the volume of water (one litre weighs one kilo), plus the bathers. For a Bahia, 400 kg empty and 900 litres of water already make 1.3 tonnes before anyone gets in; for a Grande Baie, 820 kg empty and 5,500 litres exceed 6 tonnes.

As an order of magnitude, a slab of 10 to 15 cm of reinforced concrete is common for a family hot tub; always have it designed by your builder, especially for a large hot tub or a swim spa. Give the concrete the drying time your builder recommends, often several weeks: the slab must be ready before delivery.

The timber or composite deck

Possible if the structure is calculated for this weight, spread over the whole surface of the hot tub. Have it checked, and reinforced if necessary. On a balcony or a roof terrace, the opinion of a building professional is essential.

Step 3: electricity

• Plug & Play version: it plugs into a standard electrical socket in good condition and protected by a residual current device. No dedicated circuit to create.
• Other versions and models: a dedicated circuit from the fuse board, installed by an electrician, with its residual current protection. Depending on the model, the hot tub runs on 220 V single-phase or 380 V three-phase: most product pages state this in the "Electricity and controls" section.

For the warranty, our terms of sale require the hot tub to be connected to your fuse board by a professional: keep their invoice, as it must accompany the warranty registration.

Your advisor will give you the cable size and the circuit breaker rating for your model, as well as the side of the hot tub where the technical panel is: the cable must arrive in the right place, with enough length.

Step 4: delivery

Your advisor sends you the contacts of our official carriers. The one you choose makes you an offer, with a price and a date, and arranges the delivery with you.

Before the appointment, measure the narrowest point between the lorry and the site: gate, path, door, bends. The hot tub usually travels on its side; the product page of many models gives the package dimensions, to compare with this point with a margin. If it will not fit through, talk to the carrier: a crane lift can be included in their offer.

Step 5: positioning and filling

1. Position the hot tub on its base, technical panel on the planned side, and check that it is level.
2. Have the electricity connected by your electrician (except Plug & Play version).
3. Clean the tub with a soft sponge, without abrasive products.
4. Fill it with a garden hose following the instructions; many manufacturers recommend filling through the filter housing, so that no air stays trapped in the pipes.
5. Start the filtration and heating.

Heating up takes time: with a 3,000 W heater, allow around 2.5 °C per hour for 1,000 litres (theoretical calculation), so several hours for a small hot tub and a night or more for a large one. Keep the cover closed while it heats. Our article Hot tub electricity consumption explains this calculation.

Step 6: the first few days

• Balance the water: alkalinity, pH, then sanitiser. See which hot tub water treatment.
• Get to know the controls: set temperature, filtration cycles, lighting.
• Keep your documents: purchase invoice, the hot tub's serial number and the invoice from the professional who connected it. The warranty procedures are explained on the Our warranties page.

Who does what, and when

Step	Who handles it	When
Site	You, with your advisor	Before ordering
Slab or deck reinforcement	Your builder, or you	A few weeks before delivery
Electrical circuit	Your electrician	Before delivery
Delivery	The official carrier you have chosen	On the date agreed with them
Connection and filling	Your electrician, then you	On delivery day or just after

The right reflex

Approve the site and access before ordering, not after. An advisor can do this with you from photos or by video call. Request your quote describing your site: we will check with you that everything is ready for the big day.