Although this definition is very clear, it occasionally happens, especially in old towns, that some doubt arises as to whether an existing conduit for sewage is a “drain” or a “sewer”[207] for though a conduit is of small size it maybe found to be carrying the sewage of two or more buildings, and thus is really “a sewer belonging to the local authority.” This difficulty often leads to litigation where a notice having been served upon an owner of property to put in a new drain in place of one that has been found on examination to be defective, the new work is of course commenced at the junction with the main sewer, and it is not until the new so-called drain is nearly completed that it is found to be “used for the drainage” of more than one building, and is in fact “a sewer into which the drainage of two or more buildings or premises, occupied by different persons is conveyed” (see clause quoted above), and is therefore repairable by the local authority (38 & 39 Vic. c. 55, s. 13). Where the town surveyor is in any doubt as to whether the conduit is a drain or a sewer, he should test from whence the sewage comes by passing diluted white lime or carbolic acid down the adjacent water-closets and watching whether it flows through the conduit or not, but even here he is sometimes at fault if the drains are old and dilapidated, as they do not reach the point he is watching and he is thus misled. In connection with the question of house drainage the town surveyor has the following duties to perform: (1.) To inspect all new drains that are constructed in connection with existing buildings within his district. (2.) To inspect all drains of new buildings that are constructed within his district. (3.) To inspect all defective drains within his district, serve the necessary notices in respect thereof, and inspect the works he has required to be executed whilst they are in progress. (1.) With reference to the first of these duties the following is the clause of the Public Health Act 1875 which bears upon the point: “The owner or occupier of any premises within the district of a local authority shall be entitled to cause his drains to empty into the sewers of that authority on condition of his giving such notice as may be required by that authority of his intention so to do, and of complying with the regulations of that authority in respect of the mode in which the communications between such drains and sewers are to be made, and subject to the control of any person who may be appointed by that authority to superintend the making of such communications. Any person causing a drain to empty into a sewer of a local authority without complying with the provisions of this section shall be liable to a penalty not exceeding twenty pounds, and the local authority may close any communication between a drain and sewer made in contravention of this section . . . .” (38 & 39 Vic. c. 55, s. 21).