I was going to say it’s a Midwest thing, but I’ve never quite had exactly the same type of pizza elsewhere. I’ve had similar cracker crusts in Milwaukee (Zaffiro’s, in particular is awesome, even has the party cut), St. Louis has a similar-looking pizza (but different in taste), and Northwest Indiana have their versions, too. Yes, it’s an outgrowth or expansion of these styles, but Chicago’s thin crust is also a style of its own, in my opinion, much like the Quad Cities have their own style of pizza, as does St. Louis, as does Buffalo, etc. Chicago’s is not quite as crackery, the sauce tends to run sweeter in a lot of places, it’s always cut square, the quintessential topping is dollops of Italian sausage, etc. You can be as broad or particular as you want. I’m not going to argue that Chicago style thin crust is not a subset of a general crispy thin crust found in the Midwest.
The classic rooftop water towers on factories and warehouses don’t exist to provide water pressure. They exist to provide water for firefighting, especially if there’s an interruption to the municipal supply.
They can do both.
I will grant - for the toppings - Italian meats, sausage, or beef - they’re only good in or near Chicago.
Also giardiniera. I still don’t know how I lived until I had it. A near perfect condiment. One of my local places does an insane “Italian Beef” pizza, heaped with giardiniera under mozzarella. It makes me weep, it’s so good.
I never actually thought Italian beef pizza with giardiniera could be good, but if you get it from a decent place, oh my. It might actually surpass my standard order of sausage, onions, mushrooms, and peppers.
Heh, I’ve actually found your standard to be a Chicago thing. Seems like every local pizza place I know has a minor variant on your standard. Never saw it when I lived elsewhere.
That said, it is a delicious standard. It needs a name, though.
It does. It’s just called “[INSERT NAME OF PIZZA PLACE HERE]'s Special.” 
But I’m not really kidding. Pat’s, Marie’s, D’agostino’s, Vito & Nick’s–those exact four toppings are known as the “Pat’s/Marie’s/Dags/Vito & Nick’s Special.” As you note, it’s a common theme here.
Well, yes, but the water for firefighting is the critical one.
After all, if the pressure is low for normal use, what happens? It takes longer to fill a glass of water? The water fountain runs slower? Nothing very important. Not really worth the expense and hassle of building & maintaining those tanks.
But insufficient water pressure when they are trying to fight a fire can be very serious. That is a good reason to have those tanks.
Back to the OP and a clarification of several previous posts.
The City of Chicago has two water treatment plants - one just North of Navy Pier (Jardine which has a maximum throughput of 1 BGD) and another along the South Shore (called the South Treatment rated at a meer 600-MGD). Neither of these plants, however pump water into the City’s (and suburban) water systems. Both plants serve two independent (and not interconnected) tunnel systems that have sixteen pumping stations for supplying water at recommended pressures. The oldest pumping station is the Chicago Avenue one adjacent to the Water Tower on Michigan Avenue with pumps dating back to the 1870’s (and as a special bonus you can also snack on a hot pretzel). The many high rises use tankless (or as already pointed out systems with minimal tanks to stabilize water pressure rather than serve as a source of supply) pumped systems. When I lived along LSD, whenever the power went out for long periods the City Emergency crews would have to go in and rescue the elderly and infirmed on the upper floors of the highrises because they couldn’t get water.
Not totally true. Current Building and Fire Codes require that fire water be available at rather large flow rates and for minimum durations. The municipal (city) water supply is designed to meet those requirements. Many of the buildings in Chicago that have water tanks were put in years ago and don’t meet code requirements. The fact is that there are several areas within the city limits that have problems with maintaining adequate water pressure during high demand periods (read: hot, humid summer days when residents start illegally opening fire hydrants).
I would guess that many of the buildings in New York City also have the same problem.
Well the pressure above a few hundred feet would be 0. The water doesn’t just run slower, it doesn’t run at all. It’s well worth investing in a system to provide water to your upper floors even if you don’t have fires. So you either need storage you can pump up to storage or have pumps that run anytime you need water.
When it comes to actual fire fighting you need lots and lots of water those, towers don’t provide what they need, the mechanics of getting water to that height are much more important. The towers just give them a very important head start.
Not even a few hundred feet: 50 psi at ground level will only drive water up to about 100 feet, i.e. ten stories, no higher. Without any pumps, you would not be able to fill a glass of water (or fight a fire) on any floor higher than that.
50 PSI would be pretty low for street pressure I was assuming around 90 psi. You lose about .44 pounds per foot of elevation.
Meet me half way? These guys claim 50-100 psi.
Water storage typically can serve one or more of the following functions:
[ul]
[li]To provide water for normal usage into the distribution system during high demand periods.[/li][li]To provide water for fires[/li][li]To provide a constant pressure typically for elevated water storage.[/li][/ul]For the first case, systems could size the reservoir to account for the difference between average daily demand and peak demand and then fill the reservoir up at night when water demands are greatly reduced.
There are several different types of water reservoirs used and they fulfill different needs:
[ul]
[li]Buried and ground level reservoirs that are primarily used as backup, or emergency, supply water either for use during high demand periods or they may be dedicated for fire water usage. In most cases these types of systems must use booster pumps to raise the pressure of water supplied to that of the distribution system.[/li][li]Above ground elevated tanks (or water towers) can be used to provide water for all three uses. In fact, elevated tanks may have most of their capacity dedicated to fire water usage, in which case the level of water in the tank would not be allowed to drop below that defined volume. If the tank is being used to maintain system water pressure then the level will fluctuate up and down to account for changes in water demands while trying to maintain a constant pressure.[/li][/ul]The sizing and operational criteria for any water reservoir would be defined by the types of usage described above.
Now let’s address the specific situation for Chicago. As I previously stated, the City of Chicago relies on their pumping stations as the means for providing adequate pressures (thus the lack of elevated water tanks on the city horizon). Minimum system pressure must be 20 psig or above or else the water utility is supposed to issue a boil water order. The theory being that at less than 20 psig pressure other devices connected to your water system could be at a higher pressure and actually cause backflow into the water distribution system (this is bad!). As I recall, the City of Chicago’s system goal is to maintain water pressures at any point in the distribution system within a range of 40-65 psig. Unfortunately, during periods of high demand pressures in certain areas can fall dangerously close to the 20 psig level. The lack of above ground reservoirs and the fact that the two tunnel systems are not interconnected account for many of the swings in water pressure. Of course, should a fire occur in a local area the water pressure will be diminished in order to produce the necessary flows required for firefighting.
I went on a tour of the mechanical spaces of a 14 story office building one time. Boilers and chillers and air handlers and such.
The water supply consisted of a big steel tank on the ground floor (maybe 3 or 4 thousand gallons) that was fed by city water.
Beside the tank, a little air compressor was chugging away. The empty space at the top of the tank was kept at 100 psi. The air pressure forced water to the upper floors.
I was terribly disappointed. I had expected to see rows of giant pumps with giant electric motors.
The fire fighting system was totally separate. It actually had a pump and electric motor that could be powered up during an emergency.