By ABBY SOUZA
Like Tuolumne County, Hetch Hetchy Water and Power also has been preparing for any sort of terrorist attack that could hit San Francisco's water supply.
Alexis Halstead, superintendent of operations at Hetch Hetchy, said she has met with Tuolumne County law enforcement agencies to look at ways to secure the system's dams, pipelines and reservoirs.
She has met with county Office of Emergency Services Coordinator Maureen Frank and other department heads.
Halstead also has stayed in contact with the California Department of Water Resources and California Anti-Terrorist Information Center to keep updated on what is going on at the state level.
Hetch Hetchy provides water to 2.4 million people. Officials have been working to upgrade the physical barriers around the water supply. For example, a larger boundary has been placed around the O'Shaughnessy Dam.
"We've been doing a lot of this since 9/11," Halstead said.
People are still able to walk across the dam, but because of the larger barrier, cars will not be able to drive there.
Halstead has kept the system's 130 employees informed by training them on what to look for while they drive around the Moccasin property.
"They're double-checking locks and looking for anything unusual," Halstead said.