On the morning of the fourteenth of Nisan the question arises: Must ĥametz that has been placed in the garbage also be destroyed?
If the garbage bin belongs to a Jew or is located on his property, he is obligated by rabbinical ordinance to remove the ĥametz before it becomes prohibited. The owner may pour bleach or some other foul substance on the ĥametz rendering it unfit for consumption by a dog.
If the garbage container is the property of the local authority and is located in the public domain, one need not destroy the ĥametz he placed in it before the ĥametz becomes prohibited. The local authority is not obligated to destroy it because it was not interested in acquiring the ĥametz to begin with. Its only aim was to remove it to a garbage dump.
. Igrot Moshe OĤ 3:57 states that the mere act of placing the ĥametz in the trash clearly shows that one’s intentions were to rid himself of the ĥametz. However, if the trash can belongs to him, according to Taz and MA 445:3 he has a rabbinic obligation to burn the ĥametz. However, if the trash can is in the public domain, he does not have to burn any ĥametz he placed inside the trash can. Bedikat Ĥametz U-vi’uro 3:45 adds that if the ĥametz is so filthy that clearly no person would use it for any purpose, it is considered destroyed. It also adds a novel idea in n. 130: ĥametz that is unfit for humans but suitable for dogs only must be destroyed if the ĥametz is able to cause other dough to become ĥametz. However, if the ĥametz is so filthy that it is no longer suitable to any person for any purpose, it is considered nullified and need not be destroyed (see also Piskei Teshuvot 445:7, which cites other opinions). Nevertheless, when one discards his trash into a bag, as is the modern custom, the ĥametz does not always become that dirty. Thus, if the trash can is in his domain, it is best to dispel all doubt and refrain from discarding ĥametz that is still suitable for dogs into that particular trash can in the days leading up to Pesaĥ.