How Do I Establish Paternity in Washington?

Establishing paternity, what Washington law now calls parentage, is the legal step that gives a child two recognized parents and gives a father the rights and responsibilities that come with that status. For unmarried parents in Snohomish County, it is also the gateway to child support, a parenting plan, and a place on the birth certificate. Washington offers several paths to get there, and the right one depends on your situation.

Parentage, Not Just Paternity

Washington overhauled its parentage law with the Uniform Parentage Act, chapter 26.26A RCW, which took effect in 2019 and replaced the older statute. The modern law lists the ways a parent-child relationship is established. Under RCW 26.26A.100, parentage arises through giving birth, a legal presumption, a signed acknowledgment of parentage, a court adjudication, adoption, assisted reproduction, or a valid surrogacy agreement. For most unmarried fathers, two of these paths matter most: the acknowledgment of parentage and a court adjudication.

When Parentage Is Presumed

Some parents are presumed to be parents automatically. Under RCW 26.26A.115, a person is presumed to be a parent if they are married to or in a registered domestic partnership with the person who gives birth and the child is born during that marriage or partnership, or within 300 days after it ends. The presumption also applies in certain cases where the couple marries after the birth and the person asserts parentage. This is why married couples usually do not have to take any extra step. The law already treats both spouses as parents.

For unmarried parents, there is no automatic presumption based on a relationship alone, which is exactly why an affirmative step is needed.

The Acknowledgment of Parentage

The simplest route for unmarried parents is the acknowledgment of parentage. Under RCW 26.26A.200, the person who gave birth and the alleged genetic father, an intended parent, or a presumed parent may sign an acknowledgment to establish parentage. Parents often sign this form at the hospital when the child is born, though it can be signed later.

Do not underestimate what that signature does. Under RCW 26.26A.220, a properly signed and filed acknowledgment is equivalent to a court adjudication of parentage and confers on the acknowledged parent all the rights and duties of a parent. In other words, it is not a casual form. It carries the same legal weight as a court order, and it puts the father's name on the birth certificate and obligates him to support the child.

Because the consequences are real, the law builds in a chance to reconsider, but only briefly. Under RCW 26.26A.235, a person who signed can rescind the acknowledgment by filing the proper paperwork before the earlier of sixty days after it takes effect, or the first court hearing involving the child, including a support hearing. After that window closes, the door does not slam completely, but it narrows sharply. Under RCW 26.26A.240, a signatory has up to four years to challenge the acknowledgment, and only on the limited grounds of fraud, duress, or material mistake of fact. The lesson is straightforward: sign only when you are confident, because undoing it later is difficult by design.

Establishing Parentage Through Court

When the parties do not agree, or when paternity is genuinely in question, the path runs through court. Under RCW 26.26A.400, a proceeding may be commenced to adjudicate the parentage of a child, governed by the ordinary rules of civil procedure. A parent, the person who gave birth, the alleged parent, the child, or the state's child support division, among others, can start the case.

Genetic testing is the tool that resolves disputed cases. Under RCW 26.26A.310, the court must order the child and the relevant individual to submit to genetic testing when a party files a sworn statement alleging a reasonable possibility, or denial, of genetic parentage. Once testing and any hearing are complete, the court enters an order adjudicating parentage, which then supports orders for support, residential time, and decision-making. In Snohomish County, this typically unfolds in Superior Court, often alongside the child support and parenting plan questions that flow from it.

Why Establishing Parentage Matters

Parentage is not just paperwork. It is the foundation for nearly everything else involving the child. Without it, an unmarried father generally has no legal right to a parenting plan or residential time, and the child has no legal claim to support, inheritance, or benefits like Social Security and health insurance through that parent. Establishing parentage protects the child first, by securing financial support and a relationship with both parents, and it protects the father by giving him standing to seek time with his child.

It cuts both ways, which is worth being clear-eyed about. Establishing parentage creates the duty to pay child support as well as the right to seek time with the child. For a man who is certain he is the father, that is simply the law recognizing reality. For a man who is uncertain, the time to resolve the question is before signing an acknowledgment, through testing, rather than after the rescission window has closed.

A Few Common Questions

People often ask whether they can be added to the birth certificate later. Yes. A signed acknowledgment or a court order adjudicating parentage is the mechanism, and the birth record can be amended accordingly. Others ask whether paternity can be established before the child is born. An acknowledgment may be signed before birth, though it takes effect at birth. And many ask what happens if the mother or alleged father refuses to cooperate. That is precisely what the court adjudication process and court-ordered genetic testing under RCW 26.26A.310 are for.

Talk Through Your Situation

Establishing parentage is one of the most consequential steps an unmarried parent can take, and the path you choose, signing an acknowledgment or going to court, has lasting effects on support, custody, and your relationship with your child. If you are working through paternity in Snohomish County, whether you want to secure your rights as a father or you need to resolve a disputed claim, the Law Office of Chad Foster can help you understand your options and the consequences of each. Reach out to talk through where things stand and what makes sense for you and your child.