They probably opposed building large capacity tanks on the mountaintops because it'd "spoil the view" instead relying on pumped water pressure, which obviously cannot keep up with a sudden demand that outpaces the pump capacity.
These homes in the Palisades are up on hillsides, water towers are fine to supply pressure and water but you need something else if you live at higher elevation than the water tower. In SoCal they build these big ugly tanks on the tops of the mountains.
I'm not sure where the water pressure problems were at (it obviously wasn't all of LA), but if it was in the Palisades themselves I'm going to guess its related to suddenly needing to open all the hydrants and there was nowhere near enough supply for it.
Normally, any building that sits higher than the height of the water towers would need it's own tanks and pumps. Skyscrapers always have their own water tanks, NY is a good example of this. An ugly reservoir would fill the same purpose, just larger and more centralized.
Low supply in most areas is the most likely cause, ironically in individualist low trust societies, people tend to waste a lot of resources just before a disaster strikes. If you water your lawn and your house with the garden hose your home might actually survive a forest fire, but if everyone in a big city short of water does that, the city will run out of water.
I'm not sure where the water pressure problems were at (it obviously wasn't all of LA), but if it was in the Palisades themselves I'm going to guess its related to suddenly needing to open all the hydrants and there was nowhere near enough supply for it.
Low supply in most areas is the most likely cause, ironically in individualist low trust societies, people tend to waste a lot of resources just before a disaster strikes. If you water your lawn and your house with the garden hose your home might actually survive a forest fire, but if everyone in a big city short of water does that, the city will run out of water.