[175] The sewers provided by a local authority must be sufficient to carry off the ordinary sewage and rainfall of the district, but they need not be sufficient to carry off an extraordinary flow of water caused by a storm; damage caused by that comes under the definition of damage caused by the act of God, for which there is no individual responsibility (_Ibid._ p. 20). This clause seems to insist upon sewers carrying the rainfall. [176] See chapter on “Ventilation of Sewers.” [177] A local authority is not to be held liable for not keeping their sewers cleansed at all events and under all circumstances, but only where by the exercise of reasonable care and skill they can be kept cleansed. They are, however, liable, in case they make default in observing the requirements, to have an injunction filed against them and to be restrained by injunction from allowing the continuance of the nuisance. (_Ibid._ p. 23.) [178] For the legal definition of “drain,” see the chapter on “House Drainage.” [179] Facilities must be given to enable manufacturers to send the liquids proceeding from their works into the public sewers, provided the sewers are more than sufficient for the requirements of the district, or if the liquids would not prejudicially affect the sewers, or from their temperature or otherwise be injurious in a sanitary point of view. _Vide_ Rivers Pollution Act 1876 (39 & 40 Vic. c. 75, s. 7). But this question is often greatly disputed, and has led to much litigation. [180] If everything has to be carried in a sewer, the following provisions must be made:-- (_a_) The house sewage which may be calculated from the water supply. (_b_) Manufacturers’ refuse. (_c_) Rainfall, which is a very uncertain quantity. (_d_) The subsoil water should certainly be dealt with, but it should on no account be permitted to enter the sewers themselves; separate provision under the main sewers should be provided for this purpose. [181] Messrs. Sharp, Jones and Co., of Bournemouth, make most excellent concrete pipes up to 36 inches in diameter, which can be economically and advantageously used in many instances, and are gaining every day in popularity with engineers. [182] The definition of “lands” as given in the Public Health Act 1875, is as follows:--“‘lands’ and ‘premises’ include messuages, buildings, lands, easements, and hereditaments of any tenure” (38 & 39 Vic. c. 55, s. 4). [183] Notices may be signed either by the clerk to the local authority or their surveyor (38 & 39 Vic. c. 55, s. 266). [184] The thickness of stoneware pipe sewers should be as follows: