It is the only subspecies found in Region 4. In the Intermountain Region, the Arizona Toad is confirmed in the Dixie National Forest but may possibly occur on the Humboldt-Toiyabe National Forest. This toad inhabits arroyos, streams bordered by willow and cottonwoods, washes and adjacent uplands. It can also be found along irrigation ditches, reservoirs and in flooded fields. The Southwestern Toad can be found up to 6,000 feet in elevation.
Adults are nocturnal except during the breeding season.
The height of breeding season in Utah is June. The Southwestern Toad does not depend on rainfall for breeding and breeds directly in streams and shallow ponds. The eggs are laid in 1-3 rowed strings of up to 4,000 eggs and deposited on the bottom of shallow, quiet waters among gravel, leaves, sticks, mud or clean sand. The eggs are pigmented. Larvae probably eat algae, organic debris and plant tissue.