Look for links to health data on individual County Department of Health Websites.  

Washington State Local Health Departments/Districts

http://www.doh.wa.gov/AboutUs/PublicHealthSystem/LocalHealthJurisdictions

Thurston County Department of Public Health & Social Services Department, Epidemiology, Assessment and Planning Section also publishes a handy compilation of resources, County Level Data Online.

http://www.co.thurston.wa.us/health/admin/data/docs/onlinedatasources.pdf

The Washington State Department of Health
http://www.doh.wa.gov/DataandStatisticalReports

CDC Data and Statistics: FastStats
http://www.cdc.gov/nchs/fastats/default.htm

HSL Guide: Data and Statistics Resources: Washington State
http://guides.lib.uw.edu/content.php?pid=265050&sid=2191294