Can I Modify a Child Support or Custody Order in Washington?

What Does “Substantial Change in Circumstances” Actually Mean?

Washington courts do not reopen custody or support orders simply because one parent is unhappy with the outcome. The law requires a substantial change in circumstances that was not anticipated at the time the original order was entered. What counts depends on whether you are seeking to modify support or a parenting plan.

For child support, common qualifying changes include a significant increase or decrease in either parent’s income, a child losing health insurance coverage, a child’s needs changing substantially, or simply the passage of time — Washington law permits an automatic adjustment review after a set number of years even without proving a change, provided the recalculation would result in a meaningful difference from the current order.

For parenting plans and custody, courts set a higher bar because frequent changes disrupt children’s lives. Examples that Washington courts have recognized include a parent relocating, a parent’s work schedule changing dramatically, documented substance abuse or domestic violence arising after the original order, a child’s evolving needs as they age, or one parent consistently interfering with the other’s court-ordered time.

How Is Modifying Child Support Different from Modifying a Parenting Plan?

The two modification processes share the same general framework — file a petition, serve the other parent, attend a hearing — but they carry different legal standards and practical considerations.

Child Support Modifications

Washington child support is calculated using the statutory schedule under RCW 26.19. When either parent’s income has changed meaningfully, or when the current order deviates significantly from what the schedule would produce today, the court can adjust the amount. In our experience handling Spokane-area support matters, parents are often surprised to learn that a support order can become outdated quickly — a job loss, a promotion, or a change in the child’s daycare or medical costs can all shift the numbers enough to justify a formal review.

Both parents are required to exchange current financial information. The process is relatively straightforward when both sides cooperate, but it can become contested if one parent disputes income figures or claims the other is voluntarily underemployed.

Parenting Plan Modifications

Modifying a parenting plan is governed primarily by RCW 26.09. Washington courts start from a strong presumption that the existing plan should remain in place. To overcome that presumption, you must first pass an adequate cause threshold — essentially, you must show enough preliminary evidence that a full hearing is warranted at all.

If adequate cause is found, the court then weighs what modification would be in the child’s best interests. Factors include each parent’s relationship with the child, the child’s adjustment to home and school, each parent’s willingness to support the other’s relationship with the child, and any history of family violence or substance abuse. You can learn more about how Washington courts approach these decisions in our article on what a parenting plan is and how it works.

There is one important exception: if the child is in immediate danger, Washington law allows a parent to seek an emergency temporary order without waiting for a full hearing. These situations require prompt legal advice.

What Is the Process for Filing a Modification in Spokane County?

Most modifications follow these steps in Spokane County Superior Court:

• Consult an attorney. Before filing anything, get a realistic assessment of whether your facts meet the substantial-change standard. Filing a weak petition can waste time and money — and in parenting plan cases, a frivolous filing can count against you.
• Prepare and file the petition. This includes a Petition for Modification, a proposed revised order (and a proposed parenting plan if custody is involved), and supporting declarations or financial worksheets.
• Serve the other parent. Proper legal service is required. The other parent then has a window to respond.
• Attend a hearing or negotiate a resolution. Many modifications in Spokane resolve through negotiation or mediation rather than a contested hearing. If the parties agree, the court typically approves the agreement as long as it serves the child’s best interests.
• Enter the new order. Once the court signs the modified order, it replaces the prior one and both parents are bound by its terms.

Can We Agree to Modify Without Going to Court?

Parents can absolutely reach their own agreement on support or custody changes — and many do. However, an informal agreement between parents carries no legal weight. If the other parent later violates the informal arrangement, you have no court order to enforce. Any agreed modification must be reduced to a written, signed order and filed with Spokane County Superior Court to be enforceable.

In our experience, even cooperative parents benefit from having an attorney draft or review the modified order to make sure it is complete and correctly formatted before submission to the court.

How Long Does a Modification Take in Eastern Washington?

Timelines vary. An uncontested child support modification can sometimes be completed in a matter of weeks if both parents cooperate and paperwork is in order. A contested parenting plan modification — where the other parent fights the change — can take several months, especially if the court orders a Guardian ad Litem to investigate the child’s circumstances. Spokane County Superior Court’s family law docket is active, and scheduling a contested hearing typically requires planning ahead.

Do I Need an Attorney to Modify an Order?

Technically, Washington allows parties to represent themselves. In practice, modification proceedings — especially contested ones involving children — involve legal standards, procedural rules, and strategic considerations that are easy to get wrong without legal training. A misstep at the adequate-cause stage, for example, can result in your petition being dismissed before you ever get a hearing.

Our Spokane family law attorneys handle modification cases regularly in Spokane County and throughout Eastern Washington. Whether you need to increase support after a job change, adjust a parenting schedule to reflect your child’s growing needs, or address a serious change in circumstances, we can help you evaluate your options and build the strongest possible case. Understanding the difference between legal and physical custody in Washington is also important context before pursuing a parenting plan modification.

This article is general information only and does not constitute legal advice. Every situation is different. Contact Schwab Law, P.L.L.C. at (509) 795-1894 to discuss your specific circumstances with an attorney.

Key takeaways

• Washington courts require a substantial change in circumstances before they will modify a child support or parenting plan order.
• Child support can be adjusted when income, expenses, or time-sharing has changed significantly since the last order.
• Modifying a parenting plan requires clearing an 'adequate cause' threshold first — courts protect children's stability and do not reopen custody easily.
• Informal agreements between parents are unenforceable; any modification must be entered as a court order in Spokane County Superior Court.
• Contested modifications can take months; consulting a Spokane family law attorney before filing helps you assess whether your facts meet the legal standard.

Frequently asked questions

Helpful resources

• RCW 26.09 — Dissolution of Marriage, Legal Separation, Declaration of Invalidity
• RCW 26.19 — Washington State Child Support Schedule
• Washington Courts — Family Law Self-Help
• Spokane County Superior Court

By Taylor Schaefer, Family Law Attorney · June 30, 2026 · Reviewed by the attorneys at Schwab Law, P.L.L.C.