A garden room with kitchen covers two very different projects. A tea point with a sink, a small fridge and a kettle is a services question: water in, waste out, enough power, and somewhere for the steam to go. A full kitchen alongside a bathroom and a bedroom is a self contained unit, and that raises a planning question about whether you have built a separate dwelling in the garden.
The services a kitchenette actually needs
Cold water in, a waste run to the foul system, a socket circuit that can carry a kettle and a fridge at once, and mechanical extract over anything that cooks. None of that is difficult and all of it is easier while the trench is open. A sink discharging into a soakaway or a surface water drain is not an option: kitchen waste is foul water.
Cooking changes the ventilation and the fire picture
A kettle and a microwave are one thing. A hob is another, and it brings grease laden extract, a duct that has to be cleanable, and a fire risk in a small timber building. If real cooking is planned, that belongs in the design rather than being plugged in later, and it makes the case for a masonry or fire resisting internal lining.
Where a kitchen turns the room into a dwelling
Planning treats a self contained unit with its own kitchen, bathroom and sleeping space, used independently of the main house, as a separate dwelling. That is a full planning question, it can affect council tax, and it is not something to arrive at by adding features one at a time. If an annexe is the plan, apply for it as one.
Electrical load adds up faster than people expect
A kettle alone is a substantial load, and a kettle plus a heater plus a fridge plus a workstation on a small supply is where the trip happens. The cable from the house and the consumer unit in the room should be sized for the appliances you intend, not for lighting and a laptop.
Questions people ask about garden room with kitchen
Can I put a hob in a garden room?
Physically yes, and it changes the ventilation, the fire and often the planning picture. A microwave and a kettle keep the room in incidental territory and a full cooking kitchen with sleeping accommodation does not.
Does a sink need building regulations approval?
Installing sanitary appliances and connecting to drainage is notifiable work, so yes. It is inspected and certified separately from whatever the building itself needs.
Will a kitchenette affect council tax?
A tea point will not. A self contained annexe with its own facilities can be banded separately, which is a real cost, and it is a question to ask before building rather than to discover on a bill.