Subularia aquatica is an aquatic plant in the family Brassicaceae which is known by the common name water awlwort.

This is a small herb with awl-like leaves (generally cylindrical but tapering to a sharp point), and growing from a corm above a network of bright white roots.

Tiny flowers, each only about a millimeter long, are borne on stalks.

Flowers which rise above the surface of the water open, while those that remain submersed stay closed and self-pollinate.

This plant grows in ponds, marshes, peat bogs, and other shallow, cold water bodies, often in gravel or sand.