(Halachot from the Bet Midrash of Rabbi Ovadia Yosef zt"l)
The Laws of Searching for Chametz
One must search for Chametz by candlelight. One is obligated to search in every room in the house where Chametz is found. The same applies regarding balconies, gardens, cars, and the like.
The Proper Time for the Search
The proper time for searching for Chametz is when three stars come out (if one was unable to search at this time he may still search and recite a blessing even later on during the night). One may not partake of bread or cake more than a “Kebetza” (approximately 54 grams) before searching for Chametz starting from a half-hour before the proper time of the search. Nevertheless, less than a Kebetza of bread or cake or even more than a Kebetza of fruits, vegetables, rice, and the like, may in fact be eaten before performing the search.
Sunset this year in San Diego is at approximately 7:11pm, which would make the proper time to search for Chametz 7:48pm.
The Customary Ten Pieces of Bread
Some have the custom to hide ten pieces of well-wrapped bread throughout the house, so that they may be found by the person searching for Chametz. Those who follow this custom should be exceedingly careful to write down the locations of the ten pieces of Chametz, so that in the event that one (or more) piece(s) is/are not found, they will be able to be located using this list.
Renouncing Chametz
After completing the search for Chametz, one must verbally nullify the Chametz by reciting:
“Kol Chamira De’Ika Birshuti De’La Chazitei U’dla Bi’artei Livtil Velehevei Ke’Afra De’Ar’ah.”
(English Translation: “Any Chametz (leaven) which is in my possession, which I have not seen and I have not destroyed, is hereby nullified and should be considered like the dust of the earth.”)
One must recite this verbal renunciation in a language one understands, for if not, one does not fulfill one’s obligation of renouncing Chametz. It is customary to repeat the text of the renunciation three times in order to strengthen the matter.