Who is obligated to search their home for hametz?
Obviously every homeowner is obligated to make sure that his house is free of hametz by searching for it. The Gemara on our daf asks about the case of a rental – is the renter obligated to search because the hametz belongs to him, or is the owner obligated to search because the hametz is in a house owned by him? The Ran points out that in such a case, on a Biblical level, most probably neither of them are obligated to search. The renter is not obligated, since he does not own the house; the owner is not obligated, since the hametz does not belong to him. Nevertheless, the Gemara is asking on a Rabbinic level – who is obligated to search?
The Gemara concludes that if the keys were in the hand of the renter before the evening of the 14th of Nisan, then he is obligated to search. If he only gains access to the property after that time, then the obligation to search falls upon the owner.
How about a case where someone rents a house on the 14th under the assumption that it has already been searched for hametz, only to find that it has not been searched? Can the renter claim that the transaction was a mekah ta’ut – a transaction made under false impression that would allow him to cancel the agreement?
The Gemara suggests: Come and hear a resolution to this dilemma, as Abaye said: Needless to say, that in a place where people typically do not pay a wage and hire others to conduct the search for leaven and everyone searches himself, a person prefers to fulfill the mitzva himself. However, even in a place where people pay a wage and have others search for leaven, it is not a mistaken transaction due to the fact that a person prefers to perform the mitzva with his own money. Consequently, it is not considered a mistaken transaction, as a person does not object to having to perform a mitzva.
The Ritva argues that if, in fact, people usually pay for bedika (searching) to be done, and in this case the renter entered the deal under the impression that it was already paid for, the renter will be able to demand his money back from the owner of the house. The Ran disagrees, saying that although the mitzva originally was the obligation of the owner, since it is the renter who benefits from it while the owner derives nothing from the removal of the hametz, he cannot be forced to pay for it.