Cam is dipping a grilled cheese sandwich into a bowl of tomato soup when he feels the summons. He goes ahead and grabs it. Doesn't even drop the sandwich.
"Behold, two-point-six million gallons per day of pumping capacity. The water gets squeezed through a sand filter and activated charcoal on the way up, and we change out the charcoal and re-activate it every two days. It sits in the tall tanks on the roofs, then drips down along mains embedded in walls and pathways to other buildings' roof tanks. The main sewage plant is outside the city walls, I can show you that later. What do you think?"
"Not bad for working without electricity. I'm going to guess you don't have hot running water? How's the water pressure, is taking a shower here like getting rained on?"
"We have hot water, heat is easy. But it's usually lukewarm or cold again by the time it gets to whoever's using it. Most showers aren't very strong, especially if the building's water tower isn't close to full."
"Right, so I can definitely improve things. Where are you collecting the water to begin with?"
"Some from the river in the canyon, but the city of Nel kept complaining that we drain the river too much, so I convinced Grind to pay for a drilling operation and now we get most of it from an aquifer about half a mile below ground. This was a couple years ago. The whole thing is chugging along without me, now."
"No, I do not. I just know it's there. I think we're the only city in the prefecture that collects from an aquifer, at least. Nel drains the river, Zalti pays for supply from the east in an aqueduct, and so on. How would you measure the aquifer, anyway?"
"Ways and ways. If I knew how big it was I could refill it; if I try that blind I might pop the sucker. Will Nel mind if I dam the river as long as they get the same amount of total water directed back along the same channel by the time it gets to them? Collecting energy from falling water is one of the best sources of tame lightning. I can also do floating windcatchers and solar panels but you'd want lots of them and they have a little eyesore problem - like, I can do pretty solar panels but you are kind of already using your roofspace more than I'm accustomed to humans doing."
"Nel wouldn't complain, probably, but whoever's upriver from us might. I'd have to look at some maps and do a flyover to tell if anyone's house would become a lake if you put down a dam."
"And the dam would be to power the new pumps and new everything else you make here?"
"You could get enough juice out of it to power other stuff too unless it's a really puny river. ...The hot running water thing will need to involve installing new plumbing systems in all the plumbed buildings though."
"Many buildings already have hot water plumbing. They use separate tanks on their roofs, they just need to be made hot magically."
"Oh, I may have misunderstood. Is there a separate thing at the faucet to solicit hot water, and it just doesn't work that well?"
"In most buildings, at least, yes. The problem is the tanks that supply hot water don't keep themselves hot, they must be kept hot by someone physically visiting and magicking at them, which is moderately annoying."
"Right, I can fix that, and insulate the pipes, and if that doesn't do it there can be smaller electrical tanks at more points throughout the building so that the water doesn't have to travel so far. Getting electricity from place to place involves wires. I don't have to gut a building to put wires in the walls because I'm a demon, although it will help if I can get enough access to see what I'm doing."
She yawns. "Hm. It's getting late. I wanna show you the farm downstairs and then get some sleep."
She leads him down a stairwell. "This is the temperate orchard. We also have a tropical orchard, a few floors down." It's as bright as midday sun, and as warm and moist as a Mediterranean spring. There are lots of trees- Apple trees, pear trees, cherries, various nuts.
In between the large trees are a few smaller trees, plenty of bushes, and what looks like the occasional carrot, lettuce head, or potato. They make very efficient use of the farmspace. A few people are on hovery patrol routes through the farm, inspecting various plants. One person is picking blueberries with magic.
"You know, I might be able to get you better higher-yield seeds and kinds of food you don't have, but I likely can't improve on the setup otherwise without spending a lot of time hanging out on farms personally. I'm very impressed."
She takes him on a quick tour through a few other floors. The tropical orchard is uncomfortably hot, and the cereal crop floors are boring in comparison.
"Good night, I suppose. You can find me in my office a couple hours after sunrise tomorrow."
The city is substantially quieter and less busy at night. Someone somewhere is making enough light to make main parks and roads bright enough to navigate, but most buildings are completely dark.
In addition to the strongly interconnected paths above ground, there is a network of tunnels connecting cavern-like basements. These only go down a few floors at most. Police patrol the streets, but there is a more run-down 'bad part of town' that gets fewer and more cursory patrols.
A few restaurants and stores are still open. Most of the bars and nightclubs are, too. There are only a dozen in total, it's not really a huge city after all. It'll take only a little searching to find a quiet and relatively isolated nook to read, indoors or out, if he wants to do that.
He peeps at a restaurant to see if they have a style of disposable cup he can copy so as not to stand out while drinking lots of coffee. He can always go with the more direct caffeination route if necessary, but he does like coffee.
The only disposable cups anyone uses are made of a breadlike substance that doesn't seem to absorb liquids.