Plot in flood protection area - Not recommended?

Flood protection classes are taken from maps that do not necessarily have to be very accurate. Are there any past water levels there that give an impression of what can happen or has happened? Our residential area is officially also partially in a floodplain, even though it is 20m above a small creek. Simply because at some point the map was hatched like that, xxx m to the right and left of the creek, and that’s it.

Maybe it’s not critical for you either. Otherwise: If the basement is watertight, the house becomes a boat during a flood: very dangerous. In a flood event, I would prefer a flooded and then pumped-out basement.

I possibly still see problems with financing: there was a question about that in our loan application.

[FLOOD PROTECTION CLASSES are taken from maps that do not necessarily have to be very accurate. Are there any past gauge readings there that give an impression of what can happen or has happened there? Our residential area is officially partly in a floodplain, although it is 20m above a small stream. Simply because at some point the map was hatched like that, xxx m to the right and left of the stream, and that's it.

Maybe it is not critical for you either. Otherwise: If the basement is waterproof, the house becomes a boat during a flood: Very dangerous. In that case, I would prefer a flooded and subsequently pumped-out basement.

I might still see problems with financing: there was a question about that in our loan application.]

I have not yet looked into the history of the Rhine gauge readings. The potential for the flood event to occur in an HQextrem is extremely rare but certainly exists. If you exclude the flood event itself, groundwater levels and flows are certainly problematic and, above all, what rather excludes basement construction. In the case of HQextrem, the area lies in the inundation zone with 2m according to the development plan and also the flood maps from the regional council. However, the NBG was already raised above the 2m during the development, so that with high probability the ground floor will remain dry in the event of a case. If the basement is omitted, do the special foundations also become unnecessary? Or does the base slab also have to be secured against buoyancy?

So if you are really only in the HQExtrem area with the property, I wouldn't worry about it that much. In our (Städtchen am Neckar) half the town is underwater at HQExtrem, including my little house. But that has never happened in recorded history. The building insurance doesn't care about that, they have their own maps and corresponding data (ZÜRS).

So if you are really only in the HQExtrem area with the property, I wouldn't worry too much about it.
Here with us (a small town on the Neckar), half the town is underwater at HQExtrem, including my little house.
But that has never happened in recorded history.
The building insurance doesn't care about that, they have their own maps and corresponding data (ZÜRS).

Thanks for the info. But what if I am also in the HQExtrem area according to the insurance? Or do you mean that the area is generally not relevant for the calculation? I mean, as you already said, in most cases we are probably talking about an event that statistically CAN occur > every 100 years. So you are not paying the theoretically higher risk here compared to areas where there is no risk of flooding?

As I said, the insurances draw their own conclusions from the flood hazard situation.
Google "ZÜRS Zone."
They do differentiate according to risk; the areas truly at risk of flooding simply cannot be insured against it.
You are at most danger class 2, which according to GDV concerns about 10% of the entire property stock.
My building insurance does not cost more than anywhere else, so the surcharges should also be limited.

However, a 0.5 m high retaining wall must be built for the existing building

Existing building means that there are concrete neighbors with concrete property insurances that refer to the non-built-up terrain height. You can build on that.

2 VG but only flat roof

Ouch, without a basement and without a roof. Apart from the pure plot size (does the slope count towards the floor area ratio calculation basis?), for me this reads overall as keep searching.