Personal Watercraft (PWC) restrictions in California

Each person on a PWC or being towed by a PWC must wear a USCG approved life jacket specific for the activity.
The law requires anyone operating a PWC equipped with a lanyard cut-off switch to attach the lanyard to his or her person, clothing or life jacket. Operating a PWC equipped with a self-circling device is prohibited if the device has been altered.
To operate a PWC designed for one person, the operator must be 16 years of age or older. A person 12-15 years of age may operate a PWC designed to carry two or more persons if the operator is supervised on board by a person 18 years of age or older.
It is illegal to operate a PWC from sunset to sunrise.
You may not carry more passengers than the number for which the craft was designed to carry by the manufacturer. When towing someone on a tube or on water skis, the PWC must have the appropriate capacity to accommodate the operator, the observer, and the person being towed.

Under California law, no person shall operate any craft in a reckless or negligent manner. It is prohibited to:

Follow another vessel or skier too closely.
Jump another vessel's wake within 100 feet of the vessel creating the wake.
Drive in excess of 5 mph within 200 feet of a beach
Speeding within 100 feet of swimmers.
Cut between a boat and the person being towed.
Navigate a vessel, skis or other devices between a towing vessel and its tow or tows.
Operate under the influence of intoxicants or narcotics.
Turn sharply so that it sprays the person or vessel.
Operate at a rate of speed and so close to another vessel that either operator is required to swerve at the last minute to avoid collision.