On June 12, 2008, a number of provisions of HB 3104 - 2007-08 will go into effect, which will expand the rights of registered domestic partners to include property rights previously enjoyed only by married individuals. The text of the session law can be viewed here
Under the new law, property acquired by either domestic partner after the partnership is registered will be held as community property. (Under Washington law, conveyances of real property held as community property generally require consent of both parties.) Once this law is in effect, purchasers of real property (not to mention insurers of title) should ensure that deeds and other conveyancing documents are executed and acknowledged by any domestic partner who may have a community interest in the real property conveyed.