About 50,000 gallons of partially treated wastewater mixed with rainwater spilled from a San Luis Obispo treatment facility Thursday afternoon and into a creek, prompting a nearby beach closure. According to the San Luis Obispo County Public Health Department, the sewage mixture began spilling from a treatment facility around 12:40 p.m. “due to the storm surge event.” The Department said approximately 50,000 gallons was released into San Luis Obispo Creek during the event. The spill was mitigated by 1 p.m., the release said.