The spill near York Boulevard was reported 8:53 a.m., California Highway Patrol Officer Francisco Villalobos said, adding that northbound traffic was initially taken off the freeway Avenue 60.
Caltrans notified the city's Department of Public Works at 9:20 a.m., spokeswoman Lauren Skinner said.
"Our repair crews cleared the blockage by 10:19 a.m.," she said. "Since then our crews have been cleaning up the sewage on the freeway and checking all the lines for any other blockages."
About 260 gallons of sewage flowed onto the road, and 162 gallons was recovered by DPW crews, she said.
"The other 98 gallons spilled into the Arroyo Seco Channel," Skinner said. "But that is a very small amount."
Skinner said the cleanup should be done by 2 p.m.