Detectives say he doesn't attract attention because he poses as a maintenance worker.
A surveillance camera caught the man climbing his ladder to the roof of a Santa Ana building. He made off with 240 feet of copper pipe from the air conditioning system.
Authorities believe he has also stolen copper from businesses in Fountain Valley, Cypress and Orange.
The suspect has a newer model Ford F-150 pickup truck. He is thought to be in his mid-40s to early-50s with a white beard.
Anyone with information was asked to contact Orange County Crime Stoppers at 1-855-TIP-OCCS.