A living will—also known as an Advance Health Care Directive—is a document in which the declarant or principal (person making the living will) specifies what kind of medical treatment the declarant does and does not want if the declarant has a medical emergency and is unable to communicate those wishes. A living will may direct health care providers to administer, withhold, or withdraw life-sustaining treatments if the declarant is in a terminal or irreversible condition.

Laws and terminology for documents related to living wills, Advance Health Care Directives, Do Not Resuscitate orders (DNRs), and other health care documents vary from state to state. These laws are generally located in a state’s statutes—often in the probate code or estates code.

In Washington State, a living will is known as an Advance Directive. Washington law allows individuals to create an Advance Directive to inform health care providers of their wishes regarding medical treatment if they become unable to communicate due to a serious health condition. The Advance Directive can include instructions on the administration, withholding, or withdrawal of life-sustaining treatment if the individual is in a terminal condition or is permanently unconscious. The document may also include a Health Care Power of Attorney, which appoints an agent to make health care decisions on the individual's behalf. These directives are legally binding and must be followed by health care providers. The relevant statutes can be found in the Washington Revised Code, particularly in chapters related to health care decisions and end-of-life care. It is recommended to have an attorney review the document to ensure it meets all legal requirements and accurately reflects the individual's wishes.