DIAGNOSIS The most common leak point is a crack in the plastic seam where the handle attaches to the pitcher body, or a tiny crack in the reservoir. These often come from over-tightening the lid or a drop.
FIX First, dry the pitcher completely. 1) Fill the reservoir only (the top part) and set it on a dry paper towel without the pitcher beneath it. Wait 10 minutes. If the towel is wet, the reservoir is cracked. 2) If it's dry, fill the assembled pitcher and let it sit. The leak near the handle means the main pitcher body is compromised. For either case, the fix is replacement; the parts aren't repairable.
IF THAT DIDN'T WORK Double-check the filter is seated correctly and the black rubber gasket on the bottom of the filter is present and intact. A missing gasket can cause a small drip from the filter spout, which can run down to the handle area.
HEADS UP Never put the pitcher or reservoir in the dishwasher. The high heat and harsh detergent can weaken the plastic and cause micro-cracks that lead to leaks.