16-45 inches. One pattern morph consists of dark brown to nearly black snakes with narrow tan or yellow crossbands and a pale orange band from the eye to the angle of the jaw. Another pattern morph, found in the upper Florida Parishes, consists of tan to orange-brown snakes with dark brown or gray crossbands (blonde morph). The underside is white, but heavily marked with large, alternating dark red, brown or black blotches. The keeled scales are in 21-25 rows.
Banded water snakes occur in and around most freshwater and some brackish bodies within Louisiana, and especially favor swamps. They give birth to 7-39 young. It is known to hybridize with the Salt Marsh Snake where the two species come in contact.
Throughout Louisiana except the salt marshes.