In this research work, a two-tank system in series was developed. In this system, water flows from the first tank to the second. Opening variations were present in the inlet valve, while the opening flow was fixed in the outlet valve. Using differential equations, the Jacobian matrix and eigenvalues, it was possible to analyze the stability of the system and obtain the equilibrium points. To estimate the adequate water levels, a linear and nonlinear model were implemented. Both models were able to estimate in real time the tanks water levels, identifying the system equilibrium points, this ensured the service demand. A simulation process was applied to evaluate the model’s behavior over time. This simulation was performed using the Simulink tool of Matlab. Both linear and nonlinear models obtained similar results. Results analysis suggested the use of the linear model to implement the control system, since its transfer functions compositions are less complex and more efficient to deploy.