Mr. Dinan has represented tax certificate holders in the District of Columbia since 1996 when the current system of tax sales went into effect. He represented the District of Columbia's securitized trust in the collection of tax liens, and the DC Water and Sewer Authority's assignees in their sale of Certificates of Delinquency of water bills. Mr. Dinan was one of the attorney's involved in the U.S. Supreme Court challenge to the State of New York's notice provisions. He has advised and helped draft legislation on tax sale law for the D.C. City Council.