'We don’t have water towers where I’m currently living. It’s all pump fed. And the pumps are addressable. And there’s a drought so our municipal pumps are only addressed to provide water for four hours per day!
Here’s how this works. Everyone has a cistern. They’re commercially produced, and common sizes are 450 liters, 1000 liters, and 1500 liters. They’re black, which is just perfect for heating cold water in the middle of the desert so that you can’t take a cold shower. On the other hand, I guess you save on gas consumption by not needed to heat as much (gas comes from delivery trucks, not gas lines, kind of like living in the boonies in the 'States). The cistern is plumed inline with the city water system; any time city water is available the cistern will top off automatically. The house water is drawn from the cistern, and pressure is maintained by a pump and accumulator system, probably the same as people in the 'States with wells (anyone?) or who live on mountains. Of course, if you lose electrical power, then you also lose your water. If your cistern is on the roof, you’re going to have at least a little pressure when there’s now electrical power, but with the water rationing and everyone’s cistern filling at the same time, there’s often not enough city pressure to fill your roof-mounted cistern, meaning you need yet another pump to ensure that it gets up there.
It seems that if the city ran just a couple of big pumps on a water tower, the requirement for everyone to have one or two pumps in every, single house could be eliminated. There’s be potable water when there’s no electricity. Cold water wouldn’t make it to tea-making temperatures. And as it is, I don’t know the point of these rolling water-blackouts. Our little 450 liter cistern is plenty for a whole day’s activities, including washing the patio and driveway (they do that here). There’s no conservation. There’s no net savings, and a whole lot in inconvenience, e.g., I didn’t mention that if your cistern runs dry and your pump doesn’t have a water level interlock, it will run until it burns out. Lake Huron water, how I miss thee.