Housing affordability rank

Home prices, wages and the cost of a mortgage combine to determine how affordable housing is in a specific area.

To gauge the effect on buyers, Glenn Crellin of the Washington Center for Real Estate Research at Washington State University developed a housing affordability index that ranks counties in the state.

It measures the ability of buyers earning their county's median household wage to make payments on the median-priced resale home. (Median means half are above this number, half are below.)

The index assumes that buyers make a 20 percent down payment and get a 30-year fixed-rate mortgage at prevailing rates.

Ranked from most to least affordable, here's how the 17 Washington counties in the Northwest Multiple Listing Service stack up:

1. Grant

2. Cowlitz

3. Grays Harbor

4. Lewis

5. Mason

7. Pierce

8. Kittitas

9. Kitsap

10. Clallam

11. Skagit

12. Snohomish

13. Island

14. Whatcom

15. King

16. Jefferson

17. San Juan