Sometime on July 27, someone entered the campus at 205 Vista Way, climbed over a cinder block wall that protected the school's cooling system, and removed the pipes and wiring from the system, police said.
Damage from the theft was estimated at more than $10,000, police said.
Afterward, a school district maintenance worker visited local metal recycling centers and found some of the stolen materials.
A subsequent investigation pointed police toward several suspects, and a probation search was conducted on Monday at the Delacy Avenue home of Jason Crites, 36, in unincorporated Martinez.
Investigators found stolen copper during the search, and Crites was arrested for possession of stolen property, police said.
Three other people at the home at the time of the search were arrested on suspicion of being under the influence of drugs, police said.
Two were cited and released. The third, 47-year-old Delaura Nelson, was wanted on a drug warrant and was booked into Contra Costa County Jail in Martinez along with Crites.