Interest on Child Support Arrears in Washington: Rate, Simple vs. Compound and When It Applies
Washington child support interest is 12% a year on judgments for unpaid support, whether the order came from a court or an agency. The state can collect from income and assets even while you make payments.
Does Washington charge interest on child support arrears?
Yes, Washington child support interest is 12%. All judgments for unpaid child support that have accrued under a superior court order or an order entered under the administrative procedure act bear interest at the rate of twelve percent (RCW 4.56.110(2)).
What does the Washington judgment summary show?
The judgment summary lists the amount and interest, and an application to extend must include an updated summary (6.17.020(3)). Ask the clerk for a copy to check the principal and interest figures.
What does the Washington 12% cover?
The judgments for accrued, unpaid support under a court or administrative order. The Washington arrears calculator applies it to each installment after its due month.
| Scenario at 12% simple, no payments | Interest | Total owed |
|---|---|---|
| 12 unpaid installments of $500 | $330.00 | $6,330.00 |
| 24 unpaid installments of $500 | $1,380.00 | $13,380.00 |
| 36 unpaid installments of $500 | $3,150.00 | $21,150.00 |
Each figure assumes no payments.
Is Washington child support interest simple or compound?
The statute sets one rate and does not call for compounding, so the calculator uses simple interest. Ask the Division of Child Support or the clerk how your balance was computed.
Does Washington interest run while I am paying?
Interest runs on the unpaid balance of the judgment. The state agency may collect from your income and assets even if you are making payments under the order, unless it agrees in writing to limit collection (WAC 388-14A-4000(2)).
What happens to a Washington administrative order debt?
If you fail to make the total payment due under an administrative order, the entire support debt becomes due in full and the part of the order that required periodic payments on the debt is automatically vacated without modifying the order (WAC 388-14A-4000(3)).
Does the 12% apply to support under an old order?
It applies to judgments for unpaid support that accrued under a superior court order or an administrative order (4.56.110(2)); older judgments follow the rate in force when they were entered, so ask the clerk for the rate on your judgment.
How is a partial month counted?
The statute does not say; the calculator counts each installment after the month it is due. Ask the agency for its payoff letter.
Can I stop interest by paying the principal?
Paying the principal stops further interest on that part, but interest already accrued stays owed; ask the agency for a payoff figure that shows both, and put the plan in writing (4.56.110(2)).
Does Washington interest apply to medical support or fees?
The statute speaks of judgments for unpaid child support that have accrued under an order (4.56.110(2)); ask the agency whether medical support or fee items are in your judgment and at what rate.
Can I get a statement of interest?
Ask the Division of Child Support or the clerk for a written statement of principal and interest; it is the number to check against this calculator.
Is the interest owed to the state or the family?
The statute sets the rate; who receives the interest depends on the case and any assignment, so ask the Division of Child Support how the payments in your case are distributed.
Where do you get the official figure?
From the Division of Child Support or the clerk. See whether arrears can be changed and file to modify if your circumstances changed.
Frequently asked questions
What is the Washington interest rate on child support arrears?
Twelve percent.
Does Washington interest apply to unpaid support under an administrative order?
Yes. Judgments under administrative orders bear 12% too.
Is Washington child support interest compounded?
The statute does not provide for it.
Can Washington collect from me while I make payments?
Yes, unless the agency agrees in writing to limit collection.
Where can I check my Washington child support balance?
With the Division of Child Support or the superior court clerk.
Official sources
- RCW 4.56.110: interest on judgments
- RCW 6.17.020: duration of judgments
- RCW 26.18.070: mandatory wage assignment
- RCW 26.23.060: income withholding
- RCW 74.20A.320: license noncompliance
- WAC 388-14A-4000: collection of support debt
- 15 U.S.C. 1673: restriction on garnishment
- 42 U.S.C. 652(k): denial of passports
A local family law attorney can review your situation — many offer a free consultation.
This is general information, not legal advice. It is based on the cited Washington statutes, rules and court opinions, and every case turns on its own facts. Confirm how the law applies to your situation with a licensed Washington attorney.