When a hot tub triggers planning permission, when it does not, and the building regulations corner case for indoor installations.
For the vast majority of UK gardens, a freestanding hot tub on a patio does not need planning permission. It counts as a temporary structure. The rules change once the tub is in a permanent enclosure, sunk into decking, or installed indoors.
A standalone tub on a level patio or concrete pad in your back garden, with no surrounding structure, is fine. So is a tub on a deck, provided the deck itself was built within the permitted development limits.
Listed buildings and conservation areas are the obvious exceptions. If you are in either, check with your local authority before you order. The tub is rarely the issue. The wiring, the gazebo, or the visible plant equipment usually is.
If you build a permanent gazebo or summerhouse over the tub, the gazebo itself needs to comply with permitted development rules: no taller than 2.5m at the eaves within 2m of a boundary, no more than half your garden taken up by outbuildings.
If you sink the tub into the ground or into a raised deck higher than 30cm, that counts as a structure and may need Building Control sign-off, especially for the surrounding falls and for the electrical earthing arrangement.
Front garden installations face stricter rules because of visibility and on-street parking impact. Most councils dislike them.
The electrical connection. A hardwired hot tub installation is notifiable under Part P of the Building Regulations. That means it must be done by a registered electrician (NICEIC, NAPIT, or equivalent) who issues you a compliance certificate and notifies Building Control.
This applies even to a 13A plug-in tub if you are running a dedicated outdoor circuit for it. The certificate matters when you sell the house, when you make an insurance claim, or if anyone is ever hurt by a fault.
Indoor tubs above ground floor need a structural engineer's sign-off because of the weight (a full tub plus bathers can exceed 1,500 kg) and Building Control approval for the floor loading and ventilation.
No, but you must use the foul drain (the same one your sinks use), not a surface-water drain. Discharging treated water to a soakaway in your own garden is also fine in most council areas.