The Portascanner® WATERTIGHT PRO has the highest accuracy of any leak quantification instrument of its kind. Our in-house experiments have demonstrated a high level of accuracy (within ±10%) in leak-size quantification, which has been independently verified by the National Physical Laboratory. Flowrate accuracies are subject to user error in input measurements such as seal thickness and roughness, as well as the shape of the leak, however, our empirical formulae are calibrated to the upper error bound, so you can be sure that the true waterflow rate will not significantly exceed the calculated value.