Objectives: In this work we use the bisection method through MATLAB for finding the depth of a submerged ball in a RO water tank. Material and Method: Using MATLAB, and by Bisection method, we find the depth of the submerged ball in a RO water system. Results: We know that Buoyancy (upthrust) is an upward force exerted by a fluid that opposes the weight of an immersed object. Archimedes’ principle indicates that the upward buoyant force that is exerted on a body immersed in a fluid, whether fully or partially submerged, is equal to the weight of the fluid that the body displaces and it acts in the upward direction at the centre of mass of the displaced fluid. Using this principle we have formed the polynomial equation, according to the radius of the ball submerged in water. We have solve this polynomial equation using MATLAB, and by Bisection method. This gives us the depth of the submerged ball in a RO water system. Conclusion: The polynomial equation in x we formed is a nonlinear equation. Solving it would give us the value of ‘ x ’, that is, the depth to which the floatball is submerged under water.