It's estimated 10,000 Southern Californians will be seeking respite from the heat in the cooling waters of the creek. But there are concerns about what these visitors might be doing to the water quality.
Two years ago, a number of agencies put together an educational campaign to clean up the creek. It's called "Lytle Is Vital."
"Mostly the trash. If we could get the trash removed as they bring it in, that's the biggest problem we have," said U.S. Forest Service Ranger Gabe Garcia. "The diapers, especially."
The water is monitored at five locations. Portable toilets have been added to permanent restrooms, and visitors are advised to deposit trash in containers.
"We have several volunteer groups that help us out," said U.S. Forest Service Ranger Carol Underhill. "Lytle Creek Volunteers, several others that will help out. Clean up the creek."
Some residents have seen an improvement since the campaign started.
"Yeah, it seems like it's cleaner, you know?" said local resident Carolyn Dunlap. "They're putting their stuff in trash bags, so yeah, it seems like it to me."
John Warasky used to come to the creek as a child. He didn't like what he saw Friday.
"I think those are bettering people's values when they come up to just drop a piece of trash wherever they see fit," said Warasky.
The experts seem to agree. The problem with the water in Lytle Creek can easily be made safer if every visitor would do his or her part.