If you're single, you know it's tough to buy a house in the Seattle area. Zillow just confirmed it, but the numbers may shock you.

According to a new study to be released on Friday, it takes a single person in Seattle more than 17 years to save up enough money for a 20% down payment. Couples can do it in just 7.6 years. The study bases that on putting aside 10 percent of income each year.

Any realtor will tell you it doesn't take 20 percent down to buy a home but you'll probably pay more in interest and you'll have to pay for PMI - Personal Mortgage Insurance.

Zillow says singles in Seattle can afford to buy a home up to $234,656. That's just 12 percent of the homes available on the market. Couples can go twice as high - up to $529,317 - because they have more income. Sixty-eight percent of homes on the market in Seattle fall into that category.

Related: 20% fewer homes on the market in Seattle this year

"Single buyers typically have more limited budgets, which means they are likely competing for lower-priced homes that are in high demand. Having two incomes allows buyers to compete in higher priced tiers where competition is not has stiff," said Zillow senior economist Aaron Terrazas.

Portland is even worse where singles can only afford six percent of homes on the market. Couples there can afford 73 percent of homes for sale.

If it makes you feel better, the worst is San Jose where it takes singles more than 30 years to save up a down payment. That's longer than the typical mortgage.

Nationally, it takes singles 10.8 years to save a down payment and couples just 4.6 years.