The pride of Stockton's Holiday Park -- the pool -- is completely shut down.
"It was going from the deep end all the way to the shallow end here," said Ronnie Deutscher, who is with the group that maintains the pool.
He says someone splashed a bucket of used motor oil all over the neighborhood's summer fun.
The oil can be seen soaking into the edges of absorbent pads they've deployed.
"I was devastated," Deutscher said. "Because we've been working on this thing for three or four years"
The swimming season has just started. Swim teams are just forming. And the Holiday Park pool is hiring eight lifeguards.
Now their jobs are now on hold.
"I think that's really bad. Especially for the community. The pool is supposed to be open next week, and now it's going to be delayed because of this," said Natalee Lamie, an applicant for a lifeguard position at the pool.
Inspections revealed the motor oil made it into the pool filters.
Those will have to be replaced for more than $1,000.
"This is just straight up vandalism. Because someone has it out for us ... or something," Deutscher said.