Rooms with water

Garden room with a bathroom

A WC turns a garden room from somewhere you visit into somewhere you can spend the whole day. A shower makes it a place for guests, a gym that you can use before work, or the start of something more.

Adding a shower room with WC and basin to a garden room typically adds £4,000 to £8,000. A 5 × 4 m room with a shower room comes to about £36,000 to £48,000 in all.

Begin an enquiry

WC and basin only: £2,500 to £5,000 added
Full shower room: £4,000 to £8,000 added
Space needed: From about 1.2 × 2 m
Building control: Always, for the drains

The question to answer first: where do the drains go?

Everything about a bathroom in the garden follows from the route to the drains. Waste needs a steady fall, about 1 in 40 for a 100 mm pipe, from the room to a manhole or the soil stack of the house. Every metre of distance needs another 25 mm of depth, so a room 20 metres down the garden needs its pipe about half a metre lower at the house end than at the room.

Where the room sits below the drains, or the run is long or rocky, a pumped system takes over. A macerator WC handles a toilet and basin; a small pumping station handles a shower as well. Both work well but need power, a service every year or two, and space for the unit.

Gravity to a nearby manhole: the cheapest and most reliable. Ideal when the room is within about 15 to 20 m of the house and level with it or higher.
Pumped to the house drains: for rooms lower than the house, at the bottom of a sloping garden, or where rock is close to the surface. Add roughly £1,500 to £4,000.
New connection to the sewer: rare in gardens; needs the water company's consent. Yorkshire Water handles the Harrogate area.

Rules: planning and building regulations

A WC or shower does not, on its own, take a garden room outside permitted development. What matters is the use. A room used as an office, gym or hobby room with a WC is still incidental to the house. Add a bed and it becomes living accommodation, which needs planning permission; see our garden annexes page.

The drainage always needs building regulations approval, whatever the size of the room, because new connections to drains are controlled work under Part H. Building control inspects the pipework before it is covered. The electrics for an electric shower are notifiable under Part P and must be fitted by a registered electrician or inspected.

In the Harrogate area, conservation area limits and listed building rules apply in the usual way. A soil vent pipe showing above the roof is the detail most likely to attract comment, so ask for an air admittance valve inside the room where building control allows it.

Planning the layout

A compact shower room fits in about 1.2 × 2 m: an 800 mm shower, a WC and a small basin in a line. A WC and basin alone fit in about 1 × 1.6 m. In a 5 × 4 m room, a shower room across one end still leaves a usable 5 × 3 m space.

Put the bathroom on the side nearest the house to shorten the drain run and the water supply. Keep it away from the main glazing so the view from the main room stays clean. An extractor fan is required, wired to run on after the light goes off; in a well sealed room it also protects the timber frame from condensation.

Hot water comes from an electric shower for the shower itself and a small under-sink heater for the basin, or from a compact unvented cylinder if you want proper water pressure throughout. Both need the power supply sized for them, which the electrician checks early.

Keeping it from freezing

Harrogate sits higher than Leeds or York and sees more frosts than much of Yorkshire, so frost protection is worth planning in. The water supply pipe runs at least 750 mm deep in the trench, and pipes inside the room run on warm internal walls rather than in the outer frame.

If the room will stand empty over winter, a frost thermostat on the heater keeping it above about 5°C costs little to run. The alternative is a drain-down valve so you can empty the system when you close the room for the season.

Typical prices with a bathroom

A bespoke, insulated garden room with electrics and double glazing, plus a shower room with WC and basin, gravity drainage and water supply.

Work out your own size

Room	Typical price
Office with WC and basin 4 × 3.5 m, 14 m²	£25,000 to £33,000
Garden room with shower room 5 × 4 m, 20 m²	£36,000 to £48,000
Gym or guest room with shower room 6 × 4 m, 24 m², higher specification	£52,000 to £70,500
Pumped drainage, if needed Macerator or small pumping station	£1,500 to £4,000

Typical UK prices for bespoke, insulated buildings at £1,600 to £2,000 per m² (£2,000 to £2,600 for a higher specification), from published price lists we reviewed, October 2026. A guide, not a quote.

How the bathroom gets built in

Survey the drains
Lift the manholes, check depths and falls, and decide gravity or pumped before anything else is designed.
Building control
An application covering the drainage (and the whole room if it needs one), before work starts.
Trenches and pipes
Drain, water and power laid together, tested and inspected, then backfilled.
Fit-out
Waterproofing, sanitaryware, extractor and lighting; electrics certified and drainage signed off.

Questions

Can I put a toilet in my garden room?

Yes. A WC does not by itself need planning permission if the room is used for an incidental purpose such as an office or gym, but the drainage needs building regulations approval.

How much does a garden room bathroom cost?

Typically £4,000 to £8,000 for a shower room with WC and basin, or £2,500 to £5,000 for a WC and basin alone, on top of the room. Pumped drainage adds £1,500 to £4,000.

What if my garden room is lower than the house?

A macerator or small pumping station lifts the waste to the house drains. It needs power and occasional servicing but works reliably.

Can I sleep in a garden room with a shower?

Not under permitted development. Sleeping makes it living accommodation, which needs planning permission and full building regulations approval.

Do I need a soil vent pipe through the roof?

Often an air admittance valve inside the room can be used instead, if building control agrees. It keeps the roofline clean, which helps in conservation areas.

Where our information comes from

Enquire about a room with a bathroom

Three short stages, a couple of minutes in all. Tell us about the garden and what the room is for, and we will find a builder in your part of North Yorkshire who designs and builds rooms like it.

Free to use, and we do not build anything ourselves. We name the garden room builder we have in mind before anyone contacts you.

1 of 3

Where is the house?

Postcode