How do regions handle the division of excess utility capacities?

I have two cities in a region. The old one has plenty of water, electricity and sewage treatment resources to spare. The second city I want to specialize, and not use up precious room for these utilities.

In the second city, Im warned for a water deficit. Clicking on the water button I can see Im lacking 6.9 and the GUI reports that there is 45.2 available in the region.

My problem now is although the new city buys all these resources from the old one, it doesn't buy enough. I cannot see any pattern in it. It might be a server issue, but I would expect it to not setup any trade at all if thats the case. Im getting some water, just not all I need nor all thats avilable.

What am I missing?

Solution 1:

Before answering the question directly, you need to understand a sparsely documented caveat to region play... region hubs.

Excess utility capacity is divided up equally amongst city sites in a region hub. A region hub is defined, for utility purposes, as any city connected by ROAD to a city that wants to provided utilities to other cities.

A typical region hub in the Simcity world has 4 city sites connected to it by road. Some have as many as 7. We will use the example of having 4.

EXAMPLE: City A is in a region with 16 city sites, divided into 4 region hubs.

• City A decides to specialize in coal mining, and power itself with a coal power plant using local resources to keep costs down.
• City A only needs 15Mw to operate, but the power plant constantly produces 75 Mw. Giving it 60Mw in excess capacity. This excess capacity is offered to other cities in the region hub.
• The 3 other city sites are given the choice to buy an equal 20Mw share of the excess power since 60 / 3 = 20
• City C and D do not need the excess power, as they are generating it on their own. However, city B wishes to buy more than their share. They do not have this option. City A would need to increase their capacity in order to give out a larger share to City B.

This is how the game currently operates, and it appears to be working as intended.

Solution 2:

From reddit (bug compilation):

City producing 55 excess water, only able to buy 19.5 water from it. EDIT: this appears to be a feature, splitting the amount between the available regions it can share it's water with. I still consider this a bug, as this is not how sharing should be working IMO.