Federal and state garnishment laws can be used to stop, start and avoid wage garnishment actions by consumers, creditors and collectors. Wage garnishment (except student loans) is only possible after creditors and collectors obtain a court ordered judgment for such action. The garnishment action, otherwise known as "administrative wage garnishment" can be up to 25 percent of your disposable income.
This is for wage garnishments only. The bank may have different rules or rights regarding the amount they can take out of your account directly (you should read the fine print of the loan documents you signed).