D.C. Code § 42-2015: Books of receipts and expenditures; availability for examination; annual audit.

The manager, administrator, or the board of directors, or of administration, or other form of administration specified in the bylaws, shall keep books with detailed accounts in chronological order, of the receipts and of the expenditures affecting the project and its administration and specifying the maintenance and repair expenses of the common elements and any other expenses incurred. Both said books and the vouchers accrediting the entries made thereupon shall be available for examination by the co-owners, their duly authorized agents or attorneys, at convenient hours on working days that shall be set and announced for general knowledge. All books and records shall be kept in accordance with good accounting practice and shall be audited at least once a year by an auditor outside the organization.