020) since January 1, 1995. Washington law says that when you sell your home, you must fill out a Seller Disclosure Statement (also known as Form 17).Nearly all real estate sales in Washington State require a seller disclosure statement, also known as Form 17, to be given to the buyer. By law, most sellers of real property must provide a completed Seller Disclosure Statement (aka Form 17) to any buyer. Nearly all real estate sales in Washington State require a seller disclosure statement, also known as Form 17, to be given to the buyer. Does the owner of a manufactured home that sits on leased land have to fill out Form 17 in Washington State? The Form 17 is governed under Chapter 64.06 of the Revised Code of Washington, and in the case of improved residential real estate, RCW 64.06. Learn more about the NWMLS Form 17 (or Seller Disclosure Statement). Almost all sellers in WA must complete and provide one to a buyer. The Relay For Life of Washington County, PA is dedicated to raising money for cancer research at American Cancer Society.