Adult Adoption in Washington State: Inheritance, Process, and Legal Name Changes

Adoption is not just for young children. In Washington State, adult adoptions are a remarkably popular legal procedure for families who wish to formalize a bond that has existed for years. Whether you are formalizing a relationship with a step-child you raised in Seattle, or legally connecting with a mentor in Vancouver, adopting an adult (someone 18 or older) is generally a smooth, straightforward process.

Unlike the adoption of a minor, adult adoption does not require the involvement of Child Protective Services, background checks, or stressful home studies. Most importantly, it completely severs the legal requirement to obtain consent from the biological parents. To ensure your paperwork is filed flawlessly and your estate planning goals are met, it is wise to browse our directory for a local family law attorney who can expedite the court process.

Step-by-Step Process in Washington State

The rules governing adult adoptions are found in Wash. Rev. Code § 26.33.140. Because the person being adopted is a legal adult, the process is primarily administrative, provided both parties are of sound mind and consent to the adoption.

Step-Children Over 18

The most common adult adoptions involve step-parents who waited until the child turned 18 to avoid a contentious legal battle with a biological parent. To proceed, the adoptive parent and the adult adoptee file a joint petition in their local court, such as the Clark County Superior Court, Vancouver or Snohomish County Superior Court, Everett. Both the adopter and the adoptee must sign documents affirming that they wish to create a legal parent-child relationship. Once filed, a judge will briefly review the petition to ensure no fraud is occurring before signing the final decree.

Adopting an Adult with Developmental Disabilities

If you are adopting an adult who has developmental disabilities or lacks the mental capacity to legally consent, the process overlaps with guardianship laws. In these situations, the court may appoint a Guardian ad Litem (GAL) to independently interview the adult and determine if the adoption is in their best interest. This ensures the vulnerable adult is not being exploited for financial gain.

Legal Name Change Process

Many adults choose to change their last name to match their new adoptive family. You do not need to file a separate, costly name change petition. You can simply include your desired new legal name on the adoption petition. When the judge signs the final Adoption Decree, it serves as a legal court order granting the name change, which can then be used to update your Social Security card and driver's license.

Reissuing the Birth Certificate

Once the adoption is complete, the original birth certificate is sealed. You must submit a Form DOH 422-040, Washington, Department of Health, Application for Adoption Registration to the Washington State Department of Health, Olympia. For a small fee, the state will issue a brand-new birth certificate listing the adoptive parent as the legal parent and reflecting any new name changes.

Inheritance and Estate Planning Benefits

Adult adoption dramatically alters the legal landscape of inheritance. Under Wash. Rev. Code § 11.04.015, a legally adopted adult is treated exactly the same as a biological child. If the adoptive parent passes away without a will, the adopted adult will automatically inherit their statutory share of the estate. The legal precedent In re Estate of Fleming, 143 Wash. 2d 412 (WA Supreme Court 2001) reaffirms that adopted individuals hold robust inheritance rights. Simultaneously, the adoption severs intestate inheritance rights from the biological parents whose rights were replaced.

How Much Does it Cost in Washington?

Adult adoption is relatively inexpensive compared to other family law matters.

How Long Does the Process Take?

Because there is no home study, no waiting period for biological parent appeals, and no complex background checks required, adult adoptions move very quickly. Depending on the current backlog of the local Superior Court calendar, the entire process-from filing the initial petition to standing before the judge for the final decree-usually takes between 30 to 90 days.

Frequently Asked Questions (FAQ)