For most of us, when we envision the New York skyline we think about high-flying skyscrapers. But if you look closely at the horizon on any given day in Manhattan, what you’re bound to notice are the iconic water towers dotting the rooftops like so many barnacles. They look like antiques from a bygone era (and in terms of engineering, they are) but your flush in the Big Apple is still completely dependent on them.What’s the point of them? That new Dornbracht SensorySky shower you installed would completely suck without a water tower, because all water towers do one thing: provide pressure. Most buildings in the city taller than six stories need some sort of water tower and pumping system to provide water pressure to tenants. Each foot of height provides 0.43 PSI (pounds per square Inch) of pressure, so the natural place to stick your apartment’s water tower is the rooftop. From up there, good old gravity sends the water with great force down the pipes of the building. The giant barrel is filled to the brim with glorious H2O, and basically works like a giant toilet. As a tenant uses water, the level goes down. A ballcock lets more in, and that water is pumped from the basement. (Next time you brush your teeth, be grateful for that humble ballcock.)I’ve always thought these wood towers were ancient because they look so gnarled, but most of them don’t last more than 25-35 years before they need to be replaced. Turns out even the new ones have an old look because they are made of unfinished wood that isn’t painted or chemically treated (so as not to taint drinking water). And although steel tanks are a potential option, they are four times as expensive (not to mention the issues with steel heating up and freezing, depending on the season.) So for the most part, city buildings still use wood to build their barrels. If it ain’t broke, don’t fix it!