RCW 26.09.260: Modifying a Washington Parenting Plan

To modify a parenting plan in Washington, you generally have to prove two things under RCW 26.09.260: a substantial change in circumstances has occurred since the current order was entered, and the change you’re asking for is in your child’s best interest. The change you point to has to rest on facts that either arose after the original plan or weren’t known to the court at the time. If a circumstance existed back then, or was reasonably foreseeable, the court treats it as already built into the current plan.¹

That’s the default. Several parts of the statute change the standard for specific situations, and the kind of change you want determines which track you’re on.

Minor Schedule Changes vs. Major Residential Changes

The hardest change to win is a major modification, which means shifting which parent the child lives with most of the time. The court starts with a presumption in favor of keeping the current residential schedule and will only disturb it under RCW 26.09.260(2) if one of the following is true:¹

Both parents agree to the change.
The child has already been integrated into the petitioning parent’s family with the other parent’s consent, in a way that substantially departs from the current plan.
The child’s present environment is detrimental to their physical, mental, or emotional health, and the benefit of a change outweighs the harm the change itself will cause.
The other parent has been found in contempt at least twice within three years for failing to follow the residential schedule, or has been convicted of custodial interference.

The detrimental-environment path requires a balancing test. Showing the current situation is bad isn’t enough on its own; you have to show the harm from staying outweighs the disruption of moving the child.

Minor modifications are a separate, lighter track. Under RCW 26.09.260(5), the court can adjust the residential schedule without applying the subsection (2) factors as long as the change doesn’t shift which parent has the child most of the time and doesn’t exceed twenty-four full days in a calendar year.¹ You still have to show a substantial change in circumstances, but the evidentiary burden is lighter. Parents commonly use this track when a job change, a school schedule shift, or a local move makes the existing calendar unworkable.

Changes That Aren’t About the Residential Schedule

Not every parenting plan dispute is about where the child sleeps. RCW 26.09.260(10) creates a pathway for adjustments to the parts of the plan that don’t change the residential schedule, including decision-making authority, transportation, communication rules, and holiday arrangements that don’t affect who has the child the majority of the time.¹ You still have to show a substantial change and best interest, but the court doesn’t apply the heightened subsection (2) factors.

Special Situations That Change the Standard

Relocation

When a parent with primary residential time intends to move, that triggers its own modification pathway under RCW 26.09.260(6). Either the relocating parent or the parent objecting to the move can petition without separately proving adequate cause; the proposed relocation itself satisfies that threshold.¹ The notice obligation falls on the moving parent and runs to everyone entitled to residential time or visitation under the current order.²

When a Parent Stops Showing Up

If the parent who doesn’t have primary residential time voluntarily stops exercising their scheduled time for a year or more, the other parent can ask the court to adjust the plan to reflect reality. RCW 26.09.260(8) allows the court to make changes consistent with the child’s best interests in that situation.¹ Time missed because of military duties cannot be counted toward the one-year threshold.

Harmful Conduct

Under RCW 26.09.260(4), the court can reduce or restrict the residential time of the parent who doesn’t have the child most of the time using the criteria in RCW 26.09.191, if doing so protects the child.¹ This track doesn’t require proving a substantial change in circumstances in the traditional sense; the harmful conduct itself is the basis. RCW 26.09.191 covers conduct the court must restrict (willful abandonment over an extended period, physical or emotional abuse of a child, domestic violence, sexual abuse of a child, and knowingly living with someone who has done those things) and conduct the court may restrict (neglect, long-term substance abuse that interferes with parenting, no emotional ties to the child, abusive use of conflict that endangers the child’s psychological development, or withholding the child from the other parent for a prolonged period without good cause).³ Restrictions can range from requiring supervised visitation to eliminating overnight stays.

Military Deployment

Washington gives military parents specific protections. Under RCW 26.09.260(11), when the primary residential parent receives deployment, activation, or mobilization orders that require moving a substantial distance or materially interfere with parenting, two rules apply. Any temporary custody arrangement made during the deployment ends no later than ten days after the returning parent gives notice to the temporary custodian, and absent a motion alleging immediate danger, the court must restore the original schedule. The deployment itself, and the temporary disruption it caused, cannot be treated as a change in circumstances to justify transferring residential placement away from the service member.¹ RCW 26.09.260(12) also lets a deployed parent delegate residential time to a family member, stepparent, or another person with a close relationship to the child, if the court finds the delegation serves the child’s best interest.

Filing the Petition

The main form is the Petition to Change a Parenting Plan, Residential Schedule or Custody Order, designated FL Modify 601. You also need the Summons, FL Modify 600, which notifies the other parent of the filing.⁴ Both are available from the Washington Courts website or at your county clerk’s office.

Attach a copy of the current parenting plan, lay out the specific changes you want, and lay out the facts behind them. School records, employment documentation, medical records, and communication logs are the kinds of evidence that carry weight. Vague or thinly supported claims make it harder to clear the screening step that comes next. After filing, a third party must formally serve the documents on the other parent; you can’t hand them over yourself.

Filing Fees

Filing in the same county that entered the original parenting plan costs up to $56. Filing in a different county or under a different case number can run up to $260. If you can’t afford the fee, Washington’s General Rule 34 lets you request a waiver. You qualify if your household income is at or below 125 percent of the federal poverty guideline, if you receive needs-based public assistance such as TANF, SSI, or food stamps, or if your basic living expenses leave you unable to pay even though your income exceeds that threshold.⁵ You can apply in writing or orally, and no hearing is required.

The Adequate Cause Hearing

Washington has a screening step most states don’t. After you file and the other parent’s response window closes, you have to schedule an adequate cause hearing before the case can move toward trial or mediation. The judge reviews your petition and supporting evidence to decide whether you’ve put forward enough to justify going further. If the judge finds adequate cause, the case proceeds on the merits. If not, it’s dismissed.

That gate exists to keep families out of protracted litigation over weak claims. It also means your initial petition needs to be thorough; you’re essentially making a preliminary case that a trial-worthy issue exists. Relocation cases skip this hearing entirely, because the relocation itself satisfies the threshold.¹

Bad Faith Filings

If the court finds a modification petition was filed in bad faith, it can order the filer to pay the other parent’s attorney fees and court costs. RCW 26.09.260(13) is aimed at parents who use modification petitions to harass, retaliate, or drain the other side’s resources.¹ Make sure your evidence supports a real need for change before you file.

Child Support After a Residential Change

A significant change in the residential schedule often triggers a child support recalculation. Under Washington’s guidelines, the court can deviate from the standard support calculation when the child spends a significant amount of time with the parent making payments, weighing that parent’s increased expenses during residential time against any decreased expenses for the receiving parent.⁶ The court can’t deviate if doing so would leave the receiving household unable to meet the child’s basic needs, or if the child is receiving public assistance. If your modification will substantially change the residential split, expect support to come up and bring your financial documentation.

1
Washington State Legislature. Washington Code 26.09.260 – Modification of Parenting Plan or Custody Decree
2
Washington State Legislature. Washington Code 26.09.430 – Relocation of Child
3
Washington State Legislature. Washington Code 26.09.191 – Restrictions in Temporary or Permanent Parenting Plans
4
Washington State Courts. Court Forms – Petition to Change a Parenting Plan
5
Washington State Courts. GR 34 – Waiver of Court and Clerks Fees and Charges
6
Washington State Legislature. Washington Code 26.19.075 – Standards for Deviation From the Standard Calculation