What is the source of Chazaka?

Question

There are many halachic chazakas. Most of them are halachic assumptions, such as:

1. Keeping things the way they always were - Either financial (Chezkas Marei Kama) or religious (Chezkas Tahara, Chezkas Tuma - that we assume that once something was in one state, it stays that way until we bring proof otherwise).
2. Interpersonal assumptions - e.g Chazaka She'ein Adam Meiz Panav (we assume a borrower won't lie completely to his lender), Milsa D'avida Le'Gluiya (people don't lie when their lie will be caught), etc.

What is the source of these Chazakas. Is it a Halacha LeMoshe MiSinai or is it a Sevara? If it is a Sevara, are any proofs brought that these Sevaras are true?

Answer 1

Bavli Chullin 10b:

מנא הא מלתא דאמור רבנן אוקי מילתא אחזקיה? אמר רבי שמואל בר נחמני אמר ר' יונתן, אמר קרא: ויצא הכהן מן הבית אל פתח הבית והסגיר את הבית שבעת ימים, דלמא אדנפיק ואתא בצר ליה שיעורא! אלא לאו משום דאמרינן אוקי אחזקיה.‏
Whence do we know that which the Rabbis said, "establish it based on its previous status [Chazaka]"? Rabbi Shemuel bar Nachmeni said in the name of Rabbi Yochanan: It says in the verse (Leviticus 14:38): "Then the kohen shall go out of the house to the entrance of the house, and he shall quarantine the house for seven days." Perhaps once he leaves [the house] the size [of the Tzara'at patch] shrunk below the minimum size? Rather we must say that we can establish things based on their previous status [Chazaka].