Lewis & Short

clŏācārĭum, ĭi, n. [cloaca], the duty paid for conducting the private sewers into the public ones or for maintaining and cleansing the sewers, Dig. 30, 1, 39, § 5; 7, 1, 27, § 3; cf. Becker, Antiq. II. 2, p. 121, n. 616.