Here Proposed septik tank Septic tank Consists of Top Slab, Bottom Slab with PCC Bed, Shear walls around the tank and a top cover (Opening) to check the level of Waste water. Below are the septic tank design calculations. 150mm thick buffer wall, Wastewater flows into the tank at one end and leaves the tank on the other end as shown in the figure. The septic tank is drained out with the help of suck out the outlet. The municipal Department suck out the wastage from Septic tank. , A septic tank design has to be well really thought out so that it will never crack and pollute the groundwater. In addition, they should be able to hold the weight of the wastewater. In addition, it is odorless, more importantly; it should be able to stand any kind of earth movement. A septic tank design should be good and accurate.