An estimated 25,000 gallons of sewage flowed into Atascadero Creek on Wednesday morning after a storm-related problem occurred near City Hall on El Camino Real.
At about 9:50 a.m., a blockage in a sewer siphon pipe under the Lewis Avenue bridge caused sewage to back up into the City Hall parking lot and flow into the creek, according to public works director Geoff English.
The problem was fixed by 1 p.m., officials said, after the spill was vacuumed with a pump truck and the obstruction was cleared.
City employees also cleaned and disinfected the area and, because the creek was impacted, contacted state and county environmental agencies as well as the State Department of Fish and Game, English said.
The incident and response comes six weeks after Atascadero emergency responders and several dozen others from throughout the county attended an emergency management-training seminar in Maryland funded by a $300,000 grant from the Federal Emergency Management Agency.
"While the current storm hasn't reached the level we trained for in Maryland," English said, "we are all the more prepared for such incidents because of that experience."