Plenty of people want a toilet or shower in a backyard studio, especially when it doubles as a spare room for visitors. The rules don't forbid it outright. A bathroom does change how the studio is assessed, though, and how it has to be built.
What the planning rules say
The Codes SEPP says a detached studio can't contain cooking facilities and can't function as a separate home. The definition doesn't mention bathrooms, so a toilet or shower isn't automatically ruled out. What planners and certifiers look at is the full set of facilities. A studio with a bathroom, a sink bench, a fridge space and a separate entry starts to look like a home that can run on its own, and that is a secondary dwelling under different rules.
Some councils publish guidance on what they will accept in a studio. A common position is that a toilet and shower may be fine, while a kitchen sink, cooktop, oven or fridge is not. If your design includes a bathroom, keep the rest of the fit-out clearly tied to the studio's stated use, and expect questions if it isn't.
Waterproofing: built like any bathroom
The building code counts a habitable studio as part of the Class 1 house, so a studio bathroom is built to the same standard as a bathroom inside the home. Part 10.2 of the ABCB Housing Provisions requires wet area building elements to be either waterproof or water resistant, and refers to AS 3740. In practice, expect:
- a waterproof shower floor and waterproof shower walls up to the height the code sets
- sealed junctions between walls and floors, and around pipe penetrations
- floors that fall to a floor waste where one is needed
- suitable hobs, step-downs or level-threshold details for the shower
Waterproofing is checked at a critical stage inspection before tiles go on, and the installer's certificate is needed for the occupation certificate. Our guide to Critical stage inspections: what we check and when explains the timing. Your builder can book the inspection, ideally at least 48 hours ahead.
Plumbing and drainage
A licensed plumber has to carry out all plumbing and drainage. Getting waste from a studio at the rear of the yard to the sewer is often the hard part. The studio floor may sit lower than the connection point, or the run may cross other services, and a pump may be needed. Where there is no sewer, council must approve any on-site system for treating wastewater. Stormwater from the roof also has to go somewhere lawful, and those connections are inspected before they are covered.
Ventilation, condensation and power
Small detached buildings with a shower can trap a lot of moisture. Bathroom and toilet exhaust should discharge outside, not into the roof space, and the roof and wall build-up should manage condensation. The condensation rules were updated in NCC 2025, which NSW plans to adopt on 1 May 2027; our guide to Condensation and waterproofing under NCC 2025 covers the changes. Wet area electrical work, hot water and any heated towel rail should be planned with your electrician from the start.
Thinking about a guest room?
If people will sleep in the studio, smoke alarm requirements come into play, and the space still can't become a separate home. If you want a guest to live there independently, a granny flat is the right approval.
Our backyard studios page explains how we certify studios. You can also request a quote with your plans attached.
Local help across NSW
CertifiBuild certifies Class 1 and Class 10 work in 39 council areas. Local rules on these council pages are a good place to start: Penrith City Council, City of Sydney, Shellharbour City Council, Waverley Council, Woollahra Municipal Council, Liverpool City Council.
Suburb pages with local planning notes: Edmondson Park, North Bondi, Paddington, Richmond, Shanes Park, Tullimbar, Waverley, Werrington, Willoughby East, Woollahra. You can also browse every service area.
Sources
- State Environmental Planning Policy (Exempt and Complying Development Codes) 2008, NSW Legislation
- Waterproofing wet areas (Housing Provisions 10.2), ABCB
- Building classification rules (NCC 2022 Vol. 2, Part A6), ABCB