A central feature of Cities: Skylines is the set of "growable" buildings that go up by themselves in designated construction zones. These buildings are the main source of income within the game, and so players must keep the citizens who build these structures happy.

Something else growable buildings can do is upgrade to new levels. Residential buildings have five levels each, and commercial, industrial, and office buildings have three levels. Players will want these levels to be as high as possible, because max-level workplaces can house more workers, max-level residences can hold more families, and both types of building pay more in taxes. Here's how to get those levels up.

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Education

Cities Skylines Education View

The variable with the single biggest impact on building level is education. Educated citizens will upgrade their homes and workplaces, and the better their education is the more upgrades these buildings will go through.

To educate their citizens, players will need to build up an infrastructure of elementary schools, high schools and universities. These buildings unlock at the Little Hamlet, Tiny Town, and Big Town milestones respectively. One wrinkle is that only children can go to elementary school, only teens can go to high school, and only adults can go to a university. In addition, citizens can only upgrade their education level by getting the lower level first.

Since incoming citizens who populate a new housing development are always uneducated, this means residences will always slowly improve over time, assuming the city has enough capacity for every potential student. On the other hand, industrial and office zones draw on the city's existing population, and so if the citizens are highly educated and other conditions are right these zones can upgrade very quickly.

A slight exception is that commercial buildings don't need highly skilled workers to level up, but they do need wealthy customers. However, since citizen wealth is tied to their residence level, education will still indirectly improve commercial buildings.

Service Access

Cities Skylines Deathcare View

Industrial and office zones need educated workers to improve, but they also need access to services. This includes services like health care and death care: buildings in these zones don't light up the way residential buildings do, but they still have an impact on what level these buildings can reach. Make sure the streets they're on are green so they have the best access possible. Access to entertainment and education buildings can also impact building levels in these zones, but they aren't as important as other services.

It's also worth noting that pollution and noise pollution both have negative impacts on industrial buildings, and that's despite the fact industry is a source of both. This makes it particularly hard to reach the level 3 upgrade in industrial zones without using cheats or mods.

The exception to this is specialized industry buildings. In the base game of Cities: Skylines, specialized industry districts create buildings that have only one upgrade level, and the only way players can improve them is by activating the "Industry 4.0" policy.

One other service that industry buildings in particular want is convenient access to cargo transportation. In the base game, players can provide this with the cargo train terminal that unlocks at the Small City milestone and the cargo harbor that unlocks at the Capital City milestone. Players should note that they'll need to own a map tile with a railroad or a shipping lane to make use of these buildings.

Land Value

Cities Skylines Land Value

One last factor that decides a zone building's level is land value. This is particularly important for residential and commercial buildings.

Land value goes up with access to services, and so there's a lot of overlap between this factor and the last one. However, land value is also impacted by the beauty of an area, and so pollution will drive it down while access to a waterfront will raise it up. Parks and other recreational buildings also have a big impact on land value that goes beyond the entertainment access they provide.

Looking at all these factors together, it's clear that the best way to upgrade buildings is to operate a well-run city with plenty of services and a strong education system. Just make sure that every area of the city has good access to each type of building and the zones will take care of themselves.

Cities: Skylines is available now on PC, PS4, PS5, Switch, Xbox One, and Xbox Series X/S.

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