The Code of Practice BS 5337 deals with the design and construction of reinforced and prestressed concrete service reservoirs and tanks used for the storage of water and other aqueous liquids. Structures required to retain sewage and effluents from industrial processes may also be covered by this Code depending on the degree of attack on the concrete by the liquids concerned. The recommendations are generally applicable to the storage of aqueous liquids and solutions which have little or no detrimental effect on concrete and for liquids at ambient temperatures. Some recommendations are given for the storage of corrosive liquids, for constructing tanks in soils which may contain injurious substances, and for building in areas which are liable to settlement and subsidence. No specific reference is made to the storage of oil, petrol and other liquids for which additional measures may be necessary to prevent percolation. In general, these structures will be of a simple rectangular or circular form for which guidance is given. For structures of special shape or for design in unusual circumstances, the analysis is left to the judgement of the engineer. It was assumed in drafting the Code that the design of reinforced and prestressed concrete reservoirs or tanks is entrusted to chartered engineers qualified in reinforced and prestressed concrete, for whose guidance the document has been prepared. In addition, it is anticipated that the site construction is to be carried out under the direction of an experienced supervisor. /Author/