Do taxes change when married

[Jason Morton]

my girlfriend of 4 years and I just had our offer accepted and the earnest money has been dropped off.  If everything goes well we will have our first home by Christmas.  

     We live in Vancouver Washington and neither of us believe in marriage.  But considering we do get this house, would we make more money if we were married?

     I have a friend that got married in Portland Oregon and 3 years after he was married the government started requiring them to pay more taxes. They went to a tax consultant which told them that marriage was set up for people to either have kids or buy a house.