The 50-year-old man and his pet were caught in 1 to 2 feet of rushing water under the Florence Bridge near the 5400 block of Florence Avenue at about 8 p.m.
The Los Angeles County Fire Department's Urban Search and Rescue team found the pair and hoisted them up to safety.
"We set up a two-line system off a high point off the heavy rescue, sent myself over the side, we brought up one victim and one animal that he had with him," explained rescuer Henry Diaz. "He had a reaction of relief. He was worried about his dog, and as soon as we brought him up, he was happy to be out of harm's way."
That victim, who is homeless, was loaded onto a stretcher and then loaded onto an ambulance.
The victim's son stopped by the area, trying to find his father. He said his dad has been homeless a few months after falling on hard times, and the rescue happened in an area where his father likes to stay.
The man and his dog are expected to be OK.