Storage reservoirs and overhead tank are used to store water, liquid petroleum, petroleum products and similar liquids. The force analysis of the reservoirs or tanks is about the same irrespective of the chemical nature of the product. All tanks are designed as crack free structures to eliminate any leakage. This project gives in brief, the theory behind the design of liquid retaining structure (circular water tank with flexible and rigid base and rectangular under ground water tank) using working stress method. This report also includes computer subroutines to analyze and design circular water tank with flexible and rigid base and rectangular under ground water tank. The program has been written as Macros in Microsoft Excel using Visual Basic programming language. In the end, the programs are validated with the results of manual calculation given in “Concrete Structure” book.