“While lower down payments may help pave a quicker path to homeownership for some prospective homebuyers, a bigger obstacle to homeownership is the additional non-mortgage debt many borrowers bring to the table,” Blomquist said.

For borrowers without additional debt, monthly house payments are affordable in more than 90% of U.S. housing markets whether they make a 20% or 3% down payment, he added.

“But for borrowers with the additional debt burden of student loans and car payments, monthly house payments are affordable in less than half of U.S. housing markets with a 3% down payment,” Blomquist said.

Lower down payments would likely speed up the process, he noted.

According to a report from the St. Louis Federal Reserve Bank, with a 5.6% savings rate, most consumers would take 12.5 years to save up a 20% down payment but only two years to save up a 3% down payment.

However, debt still maintained a lock on the process. Consumers without additional debt such as a student loan and a car note would be able to afford a home with even a 3% down payment in 92% of the counties RealtyTrac analyzed.

The firm found more than half of the counties or 52% had unaffordable home prices for those with either student loans, car loans or both.

RealtyTrac also discovered that most consumers don't use the more than 2,300 down payment assistance programs that are available across the country and that an estimated 60% to 80% of homes meet those programs' requirements, according to data collected by Down Payment Resource, an online real estate resource firm.

“The narrative is that it's too hard to get a loan today and when first-time buyers believe that, they won't even begin their search. That hurts the overall housing market,” Rob Chrane president/CEO of Down Payment Resource, said.

“Consumers, for the most part, have no idea that these programs exist, so they don't think to ask for them. Whatever your situation is, whatever you have for a down payment, you could be in a much better situation if you find out you are eligible for one of these programs,” Chrane said.