Legal Question in Real Estate Law in Washington

Your best option, absent working something out with your sister, is to file what is called a real estate partition action. That's a lawsuit that asks the court to either allow one of you to buy the other out, or to sell the property and divide the proceeds according to your share of ownership in the property. That's the simplest version of how I can explain it to you. Absent a contract or document specifying what portion each of you own, it can get tricky when it comes time to determine who owns what portion.