How Do I Modify Child Support Payments in Washington?

Life rarely stays the same after a support order is signed. Incomes rise and fall, children grow, and parenting schedules shift. When that happens, Washington gives parents a defined process to change a child support order, and knowing how it works can save you months of paying the wrong amount. After a layoff, gather the income records and job-search evidence needed to support a timely request. If the children's residential arrangement changes, assess whether the child-support order also needs to change.

The Two Ways to Change a Support Order

Washington law offers two doors into a support change, and they carry different burdens of proof. The first is a modification based on a substantial change of circumstances. RCW 26.09.170(1)(b) provides that, except as otherwise stated in the statute, a support order may be modified only upon a showing of a substantial change of circumstances. This is the path for a meaningful, often unexpected shift, such as a significant involuntary drop in income, a serious illness, or a change in where the children primarily live.

The second door is an adjustment that does not require proving a substantial change at all. Under RCW 26.09.170(9), once 24 months have passed from the date the order was entered or last adjusted, either parent may seek an adjustment based on changes in a parent's income or changes in the economic table or standards in chapter 26.19 RCW. Because Washington uses an income-shares model and the economic table was expanded effective January 1, 2026, an adjustment tied to updated figures can be worth exploring even when nothing dramatic has happened in your life.

The One Change That Usually Will Not Work

If you pay support and you are thinking about reducing it by leaving a job or cutting your hours, the statute closes that door. RCW 26.09.170(5)(b) states that the voluntary unemployment or voluntary underemployment of the person required to pay support is not, by itself, a substantial change of circumstances. Courts look closely at whether an income change was truly involuntary. A layoff is very different from a resignation, and the difference can decide whether your petition succeeds.

Filing the Petition: The Actual Procedure

Once you know which path fits, the mechanics of filing are set out in RCW 26.09.175. A proceeding to modify a support order begins with filing a petition and worksheets, and the petition must be in the form prescribed by the Administrator for the Courts. Washington uses standardized child support worksheets so both parents and the court are working from the same framework, which is why the statute pairs the petition with worksheets from the start.

After filing, you have to give the other parent formal notice. RCW 26.09.175(2) requires that you serve the other party with the summons, a copy of the petition, and the worksheets. If the modification is the first action filed in Washington, service must be personal. If the order being modified was entered in Washington, service may be personal or by a form of mail requiring a return receipt, and proof of service is then filed with the court. In cases where support has been assigned to the state, the attorney general or the local prosecuting attorney must also be served.

The other parent then gets a chance to respond. Under RCW 26.09.175(4), the responding party must serve an answer and worksheets and file the answer within 20 days after service, or 60 days if served out of state. Missing that deadline has consequences: the statute says a failure to answer in time results in entry of a default judgment for the petitioner.

How the Court Decides

Modification hearings in Washington usually run on paper rather than live testimony. RCW 26.09.175(6) provides that, unless the parties agree to arbitration or the court specifically allows oral testimony, a petition to modify support is heard on the affidavits, the petition, the answer, and the worksheets only. A parent who wants to present live testimony must file a motion within the time set by RCW 26.09.175(7) and show the kind of extraordinary features that justify it, such as substantial credibility questions on a major issue or particularly complex circumstances requiring expert testimony. For most families, this means the quality of your written submissions and the accuracy of your worksheets carry enormous weight.

The Division of Child Support Can File Too

Parents are not the only ones who can request a change. RCW 26.09.175(3), consistent with RCW 26.09.170, allows the Department of Social and Health services to file to modify or adjust a support order when public assistance is being paid for the child, when a party in a nonassistance case has requested a review, or when another state has requested a modification. Washington's Division of Child Support operates within that framework under chapter 26.23 RCW, so a modification can originate with the state as well as with either parent.

Orders Can Be Revisited Periodically

One of the most useful things to understand is that a support order is not meant to be permanent. The 24-month adjustment path in RCW 26.09.170(9) exists precisely so that support can be revisited as circumstances and the economic table evolve, without forcing a parent to manufacture a crisis to justify the request. If your order is more than two years old and your income or the guidelines have shifted, you may be leaving money on the table by not asking.

Timing Is Everything

Whichever path applies, file promptly. Because a court can generally modify only installments accruing after the petition is filed under RCW 26.09.170(1)(a), waiting to file means paying the old amount longer than necessary. The sooner you start, the sooner the new number can take effect.

Modifying support involves the right forms, accurate worksheets, and careful attention to deadlines. The Law Office of Chad Foster helps parents throughout Snohomish County prepare petitions that stand up to scrutiny and put them in the strongest position possible. If your circumstances or your order's age suggest a change is due, reach out to review your options.