Level 0 is the 1^st level of the Backrooms.

Level 0 resembles the back rooms of a retail outlet, and is the most common level for any individual to end up in when initially entering the Backrooms. All rooms in Level 0 appear uniform, sharing superficial features such as yellowed wallpaper, damp carpet and the occasional disabled outlet. A dropped ceiling made up of interlocked tiles and sporadically positioned fluroescent lights lies above, although the tiles are immovable.

The installed lighting flickers inconsistently and hums at a constant frequency. This buzzing is notably louder and more obtrusive than ordinary fluroescent humming. There is also a small height of space above the lights and ceiling tiles of Level 0, a dark, dust-filled area lined with wiring. Some wiring tends to be loose, which may result in faulty or disabled lights. There can also be cases of ceiling tiles having fallen onto the carpeted floor.

Linear space in this level is altered drastically; it is possible to walk in a straight line and return to the starting point, and retracing one's steps may result in a different set of rooms appearing than the ones already passed through. Due to this, and the visual similarity between rooms, consistent navigation is extremely difficult. Devices such as compasses and GPS locators fail to function within this level, and radio communications are distorted and unreliable. Note that this appears to be a pattern with any non-linear levels in the Backrooms.

No-clipping out of the bounds of reality is the most consistent way of accessing Level 0 and, by extension, The Backrooms. This level is also the most common level to end up in via no-clipping from reality.

Exiting Level 0 can be done via locating an industrial steel door, which can very rarely be found anywhere in the level. The door will lead straight to Level 1, and the door itself can be used to re-enter Level 0 if it is not lost.