The water content of nephelines from various localities were studied through thermal weight loss and single-crystal infrared spectroscopy. Typical water contents in nepheline are on the order of 0.2 to 0.5 wt. %. The H_2O molecule exists in multiple crystallographic orientations, presumably in the potassium site. Two orientations of water are indicated in the spectrum of nepheline from Monte Somma. When the crystal is heated to 350 °C, a third orientation develops.