How expensive is flood-adapted construction?

I always read that oil heating systems should not / are not allowed to be installed in flood-prone houses. Was it different in the past? I saw a house from 1979 in Köln-Weiß online – there is definitely a flood risk there, and I was surprised that the house has a normal basement and a room with an oil tank marked there.

What is your general opinion about living in such an area? My wife doesn't want it at all, but I quite like this location.

As I already wrote above, it is just an adventure. And I would always talk to the locals on site, they know best how the flooding in the area is. In our town, there is also flooding now and then, and the town center gets flooded. You are just involved, you have to clear out your rooms, check the pumps all night, and shovel/stack sandbags. It’s best if you put all your stuff in the basement into a boat right away, then it just floats upwards during a flood. But as I said, this only happens about every 5 years for us, and most residents have a certain "routine." Many simply don’t have any building insurance (too expensive) and often find themselves "stupid" in the case of damage. Some even voluntarily flood their basement with tap water because at least that is clean compared to the muddy water from the river.