You may wonder how a a toilet takes up such little space. The answer is simple: put the tank in the wall! Before now, there wasn't a system that would allow this to happen with 2x4 studs, but now there is. If square footage is important to you, checkout the innards of this system!
If you've ever wondered where they hide the tank in a wall mount toilet, wonder no longer. Geberit, known for making beautiful and minimal toilets, has created a new tank and carrier system that fits inside a standard 2" x 4" wall, allowing it to fit in smaller spaces and take up less room in smaller homes. Previously there were plenty of carrier systems designed to fit into a 2x6 space.
Bonus: It has a dual-flush valve for 0.8 and 1.6 gpf. But like all carrier models, it doesn't come cheap, and has a sticker price of $570.
(Image by Geberit)