How much tax does each zoned building generate

First, a few tips:

1. Go through every information layout possible and make sure your citizens are covered by all of the necessary services
2. Check your building levels for Residental, Commercial, Industrial/Office and try and get them up as high as possible
3. Traffic can make or break your simulation. I recommend using the "Traffic Report Tool" mod to help wrap your head around why a citizen is going where (it might help you spot missing road links!)

I am currently having your exact problem. My current has 131k population but zero demand:

As you can see my RCI is almost zero across the board. Something else must be going on here. My traffic has hardly any red spots, tons of services, and high land value in the right places. What's going on? It turns out high unemployment can cause your city to be undesirable to move in to:

But how do I have unemployment if my industry demand is zero? Personally, I have an un-even location placement of homes vs jobs.

I think this is causing my high unemployment even though there is no demand for OVERALL RCI. The industries that are far away from homes are complaining no workers are available while the residents that are far from jobs are left unemployed.

I also have a few other problems like an unnaturally low commercial percentage thanks to the park bug (BTW, thanks for the mod heads-up, I'll check it out!)

Districts don't actually do anything to restrict or direct services. Services will be user for whatever is in their local area, regardless of district boundaries (exceptions for power and water, as you distribute them manually).

Districts are useful for:

• industrial specialisation (agriculture, forestry, etc)
• policy specialisation (education boosts, tax cuts, etc)
• controlling lorries (technically a policy specialisation, by way of the heavy traffic ban, but this is important enough to warrant its own entry!)
• adding personal flavour to your city.

On that basis, the game doesn't care what districts your fire stations and fires are located in, which is why this can happen.

As to why it sends fire engines from a distant station instead of a local one (and thus, how you can prevent it), well... I'm not sure, but here's a few thoughts that may help:

• Are all the engines from the closer stations in use?
• Is that road in the middle, where the fire is, one-way in the up direction? If so this makes it "further away" from the stations on the right that it seems, and would be why it's a greater fire hazard than you might expect. It might also be confusing the distance calculation (and thus the selection of station) - consider moving one of the stations on the right downwards.