Methods and apparatus to detect leaks are disclosed. A disclosed leak probability analysis apparatus associated with a utility distribution system having sensors includes a receiver to receive spectral recording data associated with spectral recordings measured at the sensors, and a storage device to store the spectral recording data. The leak probability analysis apparatus also includes a processor to calculate spectral energies associated with the spectral recording data, calculate deviations of the spectral energies, normalize the spectral energies based on the respective deviations, and generate a leak probability distribution of the utility distribution system based on the normalized spectral energies.