Any property owned by a Jew that might contain a kezayit of ḥametz must be searched. Therefore, the kitchen and the dining room where people eat must be searched, and any room, storage space, or porch where people sometimes bring ḥametz must also be searched (SA 433:3-4).
Clothing closets that are not generally used during the course of a meal need not be searched. However, if there are children in the house, closets must be searched, because the children may have played in them while holding ḥametz or may have even hidden ḥametz in them. Closets that are too high for children to reach need not be searched.
One must search cars and carrying cases into which he sometimes places food. Adults who generally do not put food in their pockets need not search them. However, the pockets of children must be searched. Garments that were washed and had their pockets emptied out beforehand need not be searched on the night of the 14th (see below, section 8). One who does not have a home does not recite the berakha when searching his car or pockets, for the Sages instituted saying a berakha only when searching a house (Kaf Ha-ḥayim 433:91).
The stairwell of an apartment building or condominium is shared by all of the building’s occupants, and therefore they have a collective obligation to search it. In such a case, one of the occupants should be given the responsibility of performing bedikat ḥametz. Open yards need not be searched because we can reasonably assume that animals ate any ḥametz that might have been there. However, if there are alcoves in the yard that might contain ḥametz, they must be searched, because animals may not have crawled into them to eat the ḥametz. Likewise, if one knows for certain that there was ḥametz in his yard on the night of the 14th, he must search it, because he cannot be certain that animals will eat it by midday of the 14th (MB 433:27, citing Mekor Ḥayim). An enclosed porch, even if it opens into a yard, must be searched.
Ownerless public domains need not be searched, for even if they contain ḥametz, no violation has been committed. This is because such ḥametz is not in the possession of any particular Jew, and the ḥametz prohibition only applies where ḥametz is in the possession of a Jew, and not in an ownerless domain (SA 445:3; MB ad loc. 18; garbage bins are discussed below, 5:5).