Donf is correct in stating that a garnishment is an eforcement remedy available to a creditor who has obtained judgment.
The law may vary in your jurisdiction but generally speaking the only quantative restriction on garnishing a bank account is the amount of the garnishment itself. (eg. if you had $10,000 in your bank account and it was subject to a garnishment in the amount of $8,000 then you would have a balance remaining of $2,000.)
With that being said, please note that in some jurisdictions certain monies are exempt from garnishment even if they are in a bank account (ie. pensions, welfare etc).
If you are in Ontario, Canada we have more information on this topic on our website:
- Know Your Rights
In addition, if the bank account is a joint account then only half of it may be subject to garnishment.