No bone to pick in this dogfight, just piping in my two cents.
From what I understand the problem in the California fires wasn't a lack of water in combating the fires, the problem was a lack of water pressure. When a thousand fire hydrants are open at the same time guess what? Water pressure drops to nothing. You can open that hydrant up and it'll drip like grandpa's pecker. Same reason that you can't flush a toilet in one room without scalding the significant other taking a hot shower, all she's getting is stuff from the hot water tank while your crapper fills the tank with cold.