When it rains in So Cal it pours, 2" in the last week and 1.5" in the last 30 minutes is often the case. If you get caught when it's really dumping just slow down. The weight of your vehicle will keep the tires planted no matter how little tread you have unless you're driving too fast. Hydroplaning is directly related to speed, it's not like slipping on ice that can happen at any speed or even stopped, you'll only hydroplane if you're going fast enough.
You won't hydroplane pulling away from a stop sign, you may slip a little bit but you're not going to crash because of it unless you stomp on the gas pedal and steer straight into a tree. It's no different than if you were doing a burnout on dry pavement, if you start to loose control stop the spinning by letting off the throttle.