Hot Tub Installation — What's Involved in the UK

Getting a hot tub installed properly is as important as choosing the right model. A poor installation leads to long-term problems — structural damage, electrical issues, and voided warranties. Here's what's involved.

The base: non-negotiable

Your hot tub base must be:

• Solid and load-bearing — a filled hot tub weighs 1.5–3 tonnes. This needs to sit on ground engineered to support it.
• Level — to within 10mm across the entire footprint
• Larger than the tub — allow 300mm on each side for access to the equipment bay

The most reliable base is a reinforced concrete slab, 100–150mm thick on a compacted hardcore sub-base. This costs £500–£1,500 for a typical installation depending on size.

Timber decking can work if it's been specifically engineered for hot tub use — conventional garden decking will deflect and crack under the weight. Always consult a structural engineer if you're considering decking.

The electrical supply

In the UK, hot tub electrical installation must comply with BS 7671 (18th Edition wiring regulations) and Part P of the Building Regulations. This means:

• Work must be carried out by a Part P registered electrician
• A dedicated circuit from the consumer unit — not an extension lead or shared circuit
• 32A or 40A supply depending on the tub (check your manual)
• RCD protection (usually a 30mA RCD)
• Outdoor-rated cable and fittings
• Isolation switch within sight of the hot tub

Typical cost for electrical installation: £300–£600 depending on the distance from the consumer unit.

Do I need planning permission?

In most cases, no. A hot tub in a domestic garden is typically a permitted development. However, check with your local authority if:

• You're in a conservation area or AONB
• The property is listed
• You intend to build a shelter or outbuilding around the tub
• Your garden is unusually constrained in terms of permitted development rights

Water supply and drainage

You'll need a hosepipe within reach to fill the tub (typically 30–60 minutes). For draining, you'll need to discharge into a suitable drain. You cannot legally discharge hot tub water into a surface water drain (road gutter, stream) — it must go to foul drainage (the same drain as your house). The distance from tub to drain affects whether a submersible pump is needed.

What happens on installation day

1. Crane or manual delivery to position (depending on access)
2. Placement on the base and levelling
3. Electrical connection by certified electrician
4. Fill and first power-on
5. Initial commissioning — checking all jets, equipment and controls
6. Initial water chemistry balance
7. Handover and operation guidance

A standard installation takes a day. More complex installations (crane, long cable runs, large swim spas) may require two days. We handle all aspects of installation including working with electricians. Request a survey.