426. Where to Affix the Mezuzah

Tefillin, Mezuzah v’Sefer Torah 6:11

If a person typically enters and exits by an entryway between his house and a shul or a study hall, that entryway would require a mezuzah. If there is an entryway between two houses, the door’s hinge would determine the location of the mezuzah; the mezuzah is placed on the side where the hinge can be seen.

Tefillin, Mezuzah v’Sefer Torah 6:12

The mezuzah is attached on the inside of the entryway, within a handbreadth of the doorpost’s edge, in the top third of the entrance. If it was attached higher, it is still valid so long as it is at least a handbreadth below the lintel (about three inches). The mezuzah must be placed on the right-hand side as one enters the house. If the mezuzah is placed on the left-hand side, it is not valid. A house owned by partners requires a mezuzah.