Osmosensitive ion channel that mediates the cellular and behavioral response to water. Plays an essential role in gustatory water reception. Part of a complex that plays a role in tracheal liquid clearance. Probable role in sodium transport. Expressed in water-sensing neurons in taste bristles on the proboscis but not in carbonation-sensing taste peg neurons (at protein level). Expressed in the tracheal system. Flies do not exhibit any general drinking defects, but do exhibit markedly reduced water-elicited proboscis extension reflex responses. Abolishes water-elicited spiking activity of water gustatory neurons. Belongs to the amiloride-sensitive sodium channel (TC 1.A.6) family. Probable cloning artifact.