If the people of California want to buy all the BS the politicians of their state and their designated dipshits are selling more power to them. I moved so I wouldn't have to do that.
Naval ships use seawater to fight fires, but the basics on this old idea (which has been around as long as there have been ships) is that there are drawbacks in its corrosive effect. Saltwater affected metals need to cleaned afterward, like for example if your boys spray an aircraft when its leading edges are down and get all in the wing wiring and connectors, and it's also rough on the eyes when in a mist and you're using it without gear. But it's readily available.
For the coastal towns we could say well it would be smart to have some systems that remote pump from the ocean in the event the fire mains are not properly maintained due to the leadership dumbfuckery that California is plagued with. But who's got the money for that shit when they're busy cutting the fire dept every fiscal year.