Total Dynamic Head (TDH) is the amount of pressure your pump must overcome to move water vertically out of your basement and through the discharge line. If your discharge line has many turns or a steep climb, a standard pump will fail. At Basement Expert, we perform a “Head-Loss Calculation” for every site. We match your basin with a pump that has the right “Pump Curve” to ensure water actually leaves your property rather than just spinning in the pipe.