I'm planning to buy a house in 2018. My parents wants to help me out by giving me $20,000 for the down payment, what are the things I need to be aware for the audit? What are the implications from borrowing the downpayment? And what are the things I need to worry about the bank transactions? What are the questions that they are going to ask since I'm borrowing money from my parents

does anyone have any idea?

I think legally there are different processes for giving loans or even gifts. But as far as the institution giving credit, they will check your last 6 months transactions in your account and if everything looks fine they will not bother about anything. So if you want to buy in 6 months deposit the money from your parents to your account right now.

Different institutions may look at different number of months so you should check with your lender how many months bank transaction history they need from you.