The board of directors shall cause to be kept accurate minutes of their meetings and accurate records and books of account, conforming to approved methods of bookkeeping, clearly setting out and reflecting the entire operation, management and business of the district. Said books and records shall be kept at the principal place of business of the district or at such other regularly maintained place or places of business of the district as shall be designated by the board of directors, with due regard to the convenience of the district and its customers in the several localities or divisions served or from which the information is thus gathered or obtained. Said books and records shall at reasonable business hours be open to public inspection.