In re Estate of House, 2014 Wash. App. LEXIS 3006 (Wash. Ct. App. 2014) -

A release waiving any and all claims that the parties may have or may acquire, bars recovery for unknown claims existing at the time the release was executed.

Facts: Homer House had four children, and his second wife, Vera House, had two children. Homer and Vera served as co-trustees of a family trust, which they created and funded. Per the terms of the family trust agreement, at Homer’s death, Vera divided the family trust into a survivor’s trust and a decedent’s trust. Vera later transferred all the assets of the survivor’s trust to herself, and thereby terminated the trust. Shortly thereafter, Vera executed a trust termination agreement to terminate the decedent’s trust with her children and Homer’s children as parties. Additionally, the trust termination agreement mutually released and discharged the parties from any and all claims, known or unknown, that any of them had or thereafter might acquire, arising from or in any way connected with the family trust, the decedent’s trust, Homer’s estate, or their respective rights or interests under these trusts.

Two years later, Vera died testate and her children were equal beneficiaries of her estate. Four years after Vera’s death, Homer’s children learned that their paternal grandfather had a reserved interest in certain mineral rights, and a portion of the net income from this interest passed to them via the intestate succession of the grandfather’s estate. Nonetheless, Vera’s children filed a claim asserting that the mineral rights passed to them under Vera’s estate rather than to Homer’s children. In response, the personal representative of Homer’s estate petitioned for distribution of the mineral rights interest solely to Homer’s children.