16-55 inches. Dark gray, gray-green or olive above, yellow below. Young are pale gray, with a pinkish cast on the sides, with large, squared, alternating blotches. The markings of the young begin to disappear during their second year, but may persist in adults from the southwestern part of the State. The keeled scales are in 23-27 rows.
The yellow-bellied water snake can be less aquatic than the other water snakes and may be found some distance from water in wooded areas. It occurs in most habitats within Louisiana. They give birth to 14-32 young.
Throughout the state except the salt marshes.