I never signed a lease at the house I am renting a room out of. I have paid rent on time for 1 year and 9 months each month and now the owner of the house is asking me to be out by August 31st. I am going to be out before the middle of the month. Do I have to pay full rent for August even though I am leaving before month is over?

Yes, you're responsible for the rent for the entire month of August. Even though you never signed a lease you are a month to month tenant. However, try speaking to the landlord and ask them if they'll allow you to pro-rate the rent if you vacate earlier than Aug. 31st.

Yes. But often a friendly discussion such as 'gee, I'm moving out within 30 days like you wanted and not causing any trouble, and you can even work on the room before anyone else moves in, so how about 1/3 off or something' will work out OK.

If you don't have a written contract then you are considered as renting "month-to-month." In WA you must give 20 days written notice before you leave. If you send the landlord a letter today, and he receives it tomorrow, that means you have to pay through August 24 (the day he receives it doesn't count toward the 20 days).

Here's a handy resource - see page 15: http://www.lawhelp.org/documents/1593216300EN.pdf?stateabbrev=/WA/

Sounds like ebaines is on the ball on this one, I would ask, I am sure after all this time, there has to be more to it as why they are asking you to leave ?