A levy is usually issued on an account with 21 days notice. This affords the account holder the opportunity to present proof that the debt has already been satisfied, but once this claim has been made against your account, you cannot touch this money. On your daily account inquiries, your bank will list your total balance and your available balance which will differ at least the amount of any lien.
This is how the IRS operates (first hand experience).
This is how the IRS operates (first hand experience).