When, Why, and How to Change Your Order
Child support in Washington can be modified, but only under specific rules and through a formal legal process. Courts do not automatically change support when income changes or when families experience new financial realities. A judge will only modify support when a parent files the proper petition and presents clear, organized evidence. The court will not investigate the facts on its own, and it will not search for information the parents do not provide.
An attorney plays a crucial role in modification cases. A lawyer can prepare the petition or motion correctly, gather the supporting documents, and demand income information from the other parent or their employer. An attorney can also argue for changes based on special circumstances, including new children, a shift in the residential schedule, or the need to add post-secondary support before the order ends. A correct modification is an investment that affects your finances for years, because child support often continues for the entire length of a child’s education.
This page explains when modification is allowed, how it works, what evidence the court needs, and the common mistakes that lead to unfair or irreversible outcomes.
➡ For more general information visit our page Child Support In Washington State
Myths and Misconceptions About Modifying Child Support in Washington
Myth: “Child support automatically changes when income changes.”
Child support does not adjust on its own. A parent must file a petition for modification and present evidence before the court can make changes.
Myth: “We agreed verbally to change the support amount.”
Private agreements are not enforceable. The original order remains in effect until the court signs a new one.
Myth: “I can modify support at any time.”
Washington allows modifications only under the one-year and two-year rules. If an order ends before a parent files, modification is no longer possible.
Myth: “The court can fix past months if the amount was wrong.”
Courts cannot retroactively change support before the filing date except in rare situations such as fraud or clerical error.
Myth: “I can modify support after my child turns 18.”
Once support ends, the court cannot restart it. Parents must seek post-secondary support before the order expires.
Myth: “The court will check the other parent’s income for me.”
The court reviews only the evidence the parents present. Judges do not investigate or gather financial records.
Myth: “Losing my job means support will automatically decrease.”
Support does not change until you file. Waiting can lead to arrears that the court cannot erase.
Myth: “DCS or the Prosecutor will modify support for me.”
DCS and the Prosecutor only enforce the current order. They do not request modifications on behalf of either parent.
Myth: “Post-secondary support happens automatically when college starts.”
Parents must request it in advance. If you wait too long, you may permanently lose the ability to obtain college support.
Eligibility and Reasons for Modification
When can child support be modified in Washington?
Child support can be modified after one year if there has been a substantial change in circumstances, such as a meaningful change in income or a shift in the parenting schedule. After two years, support can be modified for any reason, including normal changes to income.
What qualifies as a substantial change in circumstances?
A substantial change can include job loss, increased or reduced income, disability, new childcare or medical expenses, or a major change in how much time the child spends with each parent. The change must be significant enough to affect the child support calculation.
Can I modify child support if my income changes?
Yes. Income changes are the most common basis for modification. The court requires documentation such as tax returns and recent pay stubs to verify the new income.
What is the two-year modification rule?
Washington allows parents to modify child support for any reason after two years, even without a substantial change. This makes it possible to update support based on current income.
Can I modify child support if the parenting plan changes?
Yes. A major change in residential time can justify modification, especially if the child now lives primarily with the other parent.
Do new children affect child support?
Possibly. Washington allows adjustments for children from other households, but the court evaluates the entire financial situation before changing support.
Can child support be reduced if a parent becomes disabled?
Possibly. Washington allows modification when a parent’s financial circumstances change substantially, including medically verified disability. The court will review medical documentation, earning capacity, and whether the change is expected to last.
Can child support be modified if one parent quits or changes to a lower-paying job?
It depends on whether the change was made in good faith. If the court finds the parent deliberately reduced income to avoid support, it may impute income based on past earnings instead of lowering support.
Can child support be modified if my child is now living with me more of the time?
Yes. If the child’s residential schedule changes significantly, you may request a modification to reflect the new arrangement. Courts rely on documented changes, not informal agreements.
Can child support be modified if a parent has another child?
Having additional children may justify a deviation or modification, depending on the total financial circumstances. Judges look at the needs of all children and whether the existing order remains fair.
Can I modify child support to include post-secondary support?
Yes, as long as child support is still active. Once support terminates, courts generally lose authority to add post-secondary provisions, so timing matters.
Retroactivity, Deadlines, and Timing
How far back can child support be modified?
Modifications apply only back to the date the petition was filed. Earlier months cannot be changed unless the court is correcting a clerical error or fraud.
Can child support be modified retroactively?
Child support can only be modified from the date of a petition, it cannot look back into the past. That’s why getting the petition filed as soon as possible helps ensure you have the right child support order.
What happens if I file after the child support order ends?
You cannot modify an order that has already expired. This is especially important for post-secondary support, which must be requested before the order terminates.
How long does a child support modification take in Washington?
Simple cases can be resolved within a few months, while contested cases involving income disputes or post-secondary issues take longer because the court needs additional evidence.
Can I modify child support after my child turns 18?
Possibly, but it depends on when the child support order ends. Every child support order will indicate when it ends. Some end when the child turns 18. At that point you can no longer modify the order. Others will end when the child graduates high school or turns 18, whichever is later. That means you can still modify an order if your child is 18 and has not graduated from high school yet.
Can child support be backdated to when my income changed?
Generally no. Washington does not make modifications retroactive to the date of the income change; modifications usually become effective when the petition is served. This is why filing promptly after a change is important.
Can I lower child support if I lost my job?
Possibly. Job loss may qualify as a substantial change, but the court examines whether the loss was voluntary and whether the parent is actively seeking work. Until the court modifies the order, the existing obligation continues.
Post-Secondary (College) Support
Do I have to modify my order to add post-secondary support?
Yes. Post-secondary support is not automatic. Parents must file before the child support order ends or the court loses authority to add college support.
What happens if I wait too long to request college support?
You may lose the ability to obtain any post-secondary support. Courts cannot add support after the order terminates.
Can post-secondary support be modified?
Yes. If the original order included college support, it can be modified based on scholarships, changes in expenses, or academic performance.
Evidence and Income Issues
What documents do I need to modify child support?
Parents typically provide tax returns, recent pay stubs, financial declarations, and proof of childcare or medical costs. Additional documents may be required for self-employed parents.
What if the other parent refuses to provide income information?
You can request discovery or ask the court to order disclosure. The court may draw negative inferences if the other parent refuses to cooperate.
Can the court consider cash income or under-the-table earnings?
Yes. Testimony from the other parent or financial records showing spending inconsistent with reported income can support imputation.
How does modification work for self-employed parents?
The court reviews tax returns, business records, depreciation schedules, and bank statements. An attorney can challenge improper deductions and argue for accurate income calculations.
How do deviations work in a modification?
Deviations can be requested during modification for reasons such as whole-household income, special expenses, or support obligations for other children. Parents must raise and support these requests.
Process and Procedure
How do I file a child support modification?
You file a petition to modify in Superior Court, serve the other parent, and present updated income information. The process ends with an agreed order or a hearing.
Do I have to go to court for a modification?
Most cases involve at least one hearing unless both parents agree on the new amount.
What is the difference between a modification and an adjustment?
Most modern orders do not include adjustment clauses, so parents must use the modification process. An adjustment applies only if the original order specifically includes automatic changes.
Can I modify a DCS administrative order through the court?
Yes. Parents often move DCS orders into Superior Court when financial issues become more complex.
Can I modify child support if the Prosecutor filed the original order?
Yes. Once the order is entered, you follow the same modification process as any other case.
Strategic and Cost Questions
How much does a child support modification cost in Washington?
Simple modifications usually cost between $3,000 and $6,000 dollars. Contested cases involving income disputes, new children, or college support often range from $6,000 to $18,000 dollars or more.
Is it easier to modify support through DCS or the court?
DCS is simpler for basic cases, but Superior Court offers more tools for handling complex income issues, deviations, and post-secondary support.
Why hire an attorney for a modification hearing?
An attorney prepares the petition correctly, demands income information, presents complete evidence, and argues deviations and statutory factors that parents often overlook. Attorney representation is an investment that affects child support for years.
What mistakes do parents make when modifying child support?
Parents often wait too long, fail to provide evidence, trust verbal agreements, or ignore deadlines. These errors result in incorrect orders that are difficult to fix.
Work With Pacific Northwest Family Law to Protect Your Rights During Child Support Modification
Child support modification affects your finances throughout your child’s life. Courts rely only on the evidence parents provide, and failing to file correctly or on time can permanently block changes. An attorney can prepare the right documents, gather financial information, argue for deviations, challenge improper income calculations, and help you add post-secondary support before the window closes. If you are considering a modification or worried about the current support amount, we can help you take the right steps and protect your financial future.
Reviewed by Attorney Zachary C Ashby, Pacific Northwest Family Law, November 2025.