20% down payment is required to purchase rental properties with 1-4 units. Providing that you have fairly good credit, you can use a borrowed down payment as long as it is from a source that has a verifiable monthly payment (such as a line of credit or a credit card). Proof of rental income in the form of a signed lease agreement will be required as a condition of the mortgage loan. Employment income must be verified with a letter of employment and a recent pay stub.