A new method was developed to estimate how easily water flows through an underground rock layer without stopping the water supply. By looking at how water levels change near a pumping well, scientists can figure out how fast water moves through the ground. This method doesn't require stopping the water supply for traditional tests. The closer the observation wells are to the pumping well, the simpler the solution. Even if the ground is not the same everywhere, this method can still work. If only one observation well is used, knowing how fast water diffuses through the ground is needed to find out how easily water flows.