In Washington State, the amount that a creditor can garnish from your paycheck is limited by state and federal law. Under federal law, the maximum amount that can be garnished is the lesser of 20% of your disposable income (what's left after legally required deductions like taxes) or the amount by which your weekly disposable income exceeds 30 times the federal minimum wage.
So this means you can get garnished 20% from each and every check.