Maverick's is where the biggest waves on the West Coast come in somewhat regular cycles
But, waves of 10 feet or more are not unusual anywhere in California. But, you really have to know what you are doing when waves are above about 5 feet in elevation or more because anything above about 5 feet high waves starts to get pretty dangerous. Even 5 foot waves if they aren't breaking right can be really really dangerous especially if there are rocks and sand being churned up in bad waves or conditions. Unless you are familiar with the conditions at a particular beach you shouldn't go in generally speaking.
For example, there is one beach that no one goes in the water near us that over 30 people have died there. Because if you go in you cannot swim out off this beach and people, especially divers die there all the time because they don't understand this about the beach. On this beach if you have a boat you will be okay but if you don't and go into the water you could easily die there like 30 others so far.