King County, Washington - Co-Parenting Expense & Child Support Guide

Overview

King County (Seattle metro) follows Washington's statewide child support rules in chapter RCW 26.19. The support amount is worked out the same way in every Washington county. King County Superior Court rules govern how you file and when you are heard, not how much support is owed.

Child Support Calculation

How Washington gets to a number

Washington uses an income shares model. There is no flat percentage of income in Washington law. The amount comes out of a table written into the statute, so it does not rise in a straight line as income rises. Four steps:

1. 1. Work out each parent's monthly net income - the income listed in RCW 26.19.071(3), minus the deductions listed in RCW 26.19.071(5).
2. 2. Add both parents' monthly net incomes together.
3. 3. Look that combined figure up against the number of children in the economic table at RCW 26.19.020. The table gives a basic support obligation per child.
4. 4. Split that basic obligation between the parents in proportion to each parent's share of the combined monthly net income (RCW 26.19.080(1)).

Below the bottom row of the table. That same table section - not the limits section further down this page - says what happens when there is very little income to work with. For combined monthly net income under $2,200 the table does not set the amount, and the obligation is based on the resources and living expenses of each household. Even there, minimum support may not be less than $50 per child per month, except where RCW 26.19.065(2) allows less.

The Washington State Child Support Schedule worksheets do this arithmetic for you, and the state runs a free calculator. Both are linked at the bottom of this page.

Income and deductions (RCW 26.19.071)

Gross monthly income includes, among other things:

• Salaries, wages, commissions, bonuses, and contract-related benefits
• Overtime and income from second jobs, with limited exceptions
• Dividends, interest, trust income, annuities, and capital gains
• Pension retirement benefits and severance pay
• Unemployment, workers' compensation, disability insurance, and social security
• Maintenance actually received
• Self-employment, rent, royalties, and business income

Income of a new spouse or domestic partner, child support received from other relationships, gifts and prizes, and needs-based public assistance are disclosed but are not counted as gross income.

Deducted from gross income to reach net income:

• Federal and state income taxes
• FICA (Social Security and Medicare)
• Mandatory pension plan payments and mandatory union or professional dues
• Other mandatory state deductions, including paid family and medical leave and the long-term services and supports trust program
• State industrial insurance premiums
• Court-ordered maintenance, to the extent actually paid
• Up to $5,000 per year of voluntary retirement contributions actually made, if there is a pattern of contributions in the year before the order
• Normal business expenses and self-employment taxes for self-employed parents

Floors and ceilings (RCW 26.19.065)

• Top of the table: the economic table is presumptive for combined monthly net income up to and including $50,000. Above that, a court may order more than the table amount, but only on written findings of fact.
• 45 percent limit: neither parent's support obligation for all of that parent's biological or legal children may exceed 45 percent of that parent's net income, except for good cause shown - which the statute says includes substantial wealth, children with day care expenses, special medical, educational, or psychological need, and larger families. It is not an automatic cap: before applying it the court must consider whether applying it would be unjust, weighing the child's best interests and each parent's circumstances, including whether it would leave the other household short of the child's basic needs.
• Presumptive minimum: where a parent's monthly net income is below 180 percent of the federal poverty guideline for a one-person family, an order of not less than $50 per child per month is entered unless the paying parent shows it would be unjust in that particular case. The burden sits on the parent asking to go below it, not on the court.
• Self-support reserve: the same 180 percent of the federal poverty level for a one-person family is also a floor under the paying parent's own income. The basic support obligation of the parent making the transfer payment - not counting health care, day care, and special child rearing expenses - may not push that parent's net income below the reserve. The exceptions are the $50 per child per month presumptive minimum, and a court finding that applying the reserve would be unjust after weighing the child's best interests and each parent's circumstances. Where a parent's income is already above the reserve, their basic support obligation for all of their children may not drop them below it either, again except for that $50 per child minimum.

When The Court Can Order A Different Amount (RCW 26.19.075)

The figure the worksheets produce is called the standard calculation. It is what the court orders unless it writes down specific reasons to depart from it, backed by evidence. A departure is called a deviation, and RCW 26.19.075 lists the reasons that count.

The residential schedule - the one most co-parents ask about

The court may deviate if the child spends a significant amount of time with the parent who makes the support transfer payment. Three things go with that:

• The court may not deviate on this basis if the deviation would leave the household receiving the support without enough to meet the child's basic needs, or if the child is receiving temporary assistance for needy families.
• In setting the size of the deviation, the court weighs the extra costs the paying parent takes on because of that time, and the reduced costs, if any, to the parent receiving the support.
• "Significant" is not defined as a percentage anywhere in the chapter, and a shared residential schedule does not reduce the amount automatically. It is a request the court can grant or refuse.

The other listed reasons

• Where the money comes from, and tax planning: a new spouse's or domestic partner's income, and the income of other adults in the household, but only where the parent living with them is already asking for a deviation on some other ground, and never on their own; child support actually received from other relationships; gifts; prizes; wealth such as savings, investments, property, vehicles, pensions, or business interests; a child's own extraordinary income; and tax planning, which counts only if the child ends up no worse off.
• Income that does not repeat: where part of the income used in the calculation is not a recurring source - overtime, bonuses, contract-related benefits, or a second job. The court looks at what was received in the previous two calendar years.
• Debt and high expenses: extraordinary debt not taken on voluntarily; a large gap in the parents' living costs caused by things outside their control; the special needs of disabled children; special medical, educational, or psychological needs of the children; and costs of complying with court-ordered reunification efforts.
• Children from other relationships: where either parent owes a duty of support to children who are not part of this case. Those children are not counted in the number of children used for the basic obligation, and the court looks at the total circumstances of both households.

How a deviation actually gets decided

• The court works out the standard calculation for each parent first, and only then considers reasons to deviate.
• The court must enter written findings giving the reasons for any deviation - and also for refusing one a party asked for.
• The parents simply agreeing is not, by itself, an adequate reason to deviate.
• All income and resources of the parents, of new spouses or domestic partners, and of other adults in the households must be disclosed.

Costs Shared On Top Of Basic Support (RCW 26.19.080)

Some costs are deliberately left out of the economic table and shared separately. Under RCW 26.19.080 they are split in the same proportion as the basic support obligation - the same income shares split, not 50/50.

Health care costs

Health care costs are not in the economic table. The statute lists medical, dental, orthodontia, vision, chiropractic, mental health treatment, prescription medications, and other similar costs of care and treatment.

Day care and special child rearing expenses

Day care and special child rearing expenses are also outside the table. The statute gives tuition and long-distance transportation to and from the parents for visitation as examples.

These costs are ordered in advance, so what is actually spent can come in under what was ordered. If the parent who makes the support transfer payment - the statute calls that parent the obligor - pays court-ordered or administratively ordered day care or special child rearing expenses that are not actually incurred, the other parent must repay the overpayment once it reaches at least 20 percent of the paying parent's own annual day care or special child rearing expenses. The 20 percent is measured against the payer's expenses, not the other parent's.

Two mechanics get left out of most summaries of this rule:

• Any repayment the court orders is applied first as an offset against child support arrears the paying parent owes.
• If the paying parent is not behind, the repayment can be a direct payment from the other parent, or a credit against future support payments - and a credit is spread equally over 12 months, not taken in one lump.

The paying parent can ask the superior court for this reimbursement, or apply for an adjudicative hearing with the Department of Social and Health Services. Both of those are requests to someone else. The statute closes by saying that, without the other parent's agreement, nothing in it entitles the paying parent to pay more than their proportionate share of day care or other special child rearing expenses in advance and then deduct the overpayment from future support transfer payments. In plain terms: the credit described above is something a court or the agency orders, not something you may take for yourself by short-paying support.

Who decides what is reasonable

RCW 26.19.080(4) leaves it to the court's discretion to decide whether amounts ordered above the basic support obligation are necessary and reasonable. Chapter RCW 26.19 does not set a deadline for asking the other parent to reimburse you, so the terms of your own support order control. Keep dated receipts and a written record of every request either way.

Key Forms

These are the statewide forms published by the Washington Courts. Current versions and instructions are on the court forms pages linked at the bottom of this page.

• Petition to Modify Child Support: FL Modify 501, filed with the summons FL Modify 500
• Financial Declaration: FL All Family 131
• Child Support Worksheets: WSCSS-Worksheets
• Washington State Child Support Schedule: WSCSS-Schedule, which carries the definitions, standards, instructions, and the economic table

Child support matters for King County residents are heard in King County Superior Court. Filing steps, fees, and hearing schedules change, so check the court's own page rather than any figure printed here.

Why SharedAnchor Fits King County

• Proportional splits, not 50/50: health care, day care, and special child rearing expenses are shared in the same proportion as basic support. SharedAnchor records each expense with the split that was applied, so the arithmetic is visible to both parents.
• A dated record of every request: chapter RCW 26.19 sets no reimbursement deadline, which makes your own order and your own paper trail the thing that decides a disagreement. Every expense is timestamped and hash-chained when it is added.
• Dispute prevention: both parents see every shared expense as it is added, which heads off the "I don't remember that" argument before it starts.
• Export you can hand to a lawyer: the ledger exports as a complete, tamper-evident history rather than a folder of screenshots.
• Support modification data: if either parent asks the court to change the order under RCW 26.09.170, the expense history shows what has actually been spent.