A pour over will is a will of a person made in conjunction with a trust in which all property is designated to be distributed or managed upon the death of the person whose possessions are in trust, leaving all property to the trust. A pour over will is a safety measure designed to protect any assets which somehow were not included in the trust and make them assets of the trust upon the party's death. A pour over will often provides that if the trust is invalid in whole or in part, the distribution under the will must be made under the same terms as stated in the invalid trust.
To prevent the creation of an intestate estate, a pour-over will is created to save any property which had been left out of the trust at the time of trustor's death. By the terms of the pour-over will, the property that it catches is distributed to the existing trust. A pour over will is a necessary addition to a trust, in order to protect the property which was not held by the Trust, not held in joint tenancy, or subject to other contractual arrangements at the time of the rustor's death.