Alisma plantago-aquatica is a hairless plant that grows in shallow water, consists of a fibrous root, several basal long stemmed leaves 15–30 centimetres (6–12 inches) long, and a triangular stem up to 1 metre (3+1⁄2 feet) tall.

It has branched inflorescence bearing numerous small flowers, 1 cm (1⁄2 in) across, with three round or slightly jagged, white or pale purple petals.

Narrow-leaved water plantain Alisma lanceolatum differs only in that the leaf tips are acuminate and shape is narrow lanceolate.

[5] The species is widespread across most of Europe and Asia from Portugal and Morocco to Japan, Kamchatka and Vietnam.

[6] It is reportedly naturalized in southern Africa, New Zealand, Alaska, British Columbia, Washington state and Connecticut.

[7][8][9] Some sources maintain that the species is widespread across North America, but these reports appear to have been based on misidentified specimens.