As of January 1st, 2010 all unpaid 2009 tax bills became delinquent.  Missouri Revised Statutes state: The failure of the taxpayer to receive the notice provided for in section 52.230, RSMo in no case relieves the taxpayer of any tax liability imposed [on him] by law.  Penalties for delinquent taxes are 9% in January and 2% per month through September for a total of 25% per year.  The penalties start over on January 1st of the following year if taxes remain unpaid.  State statutes require the collector's office to collect the oldest unpaid taxes first.