Final inspection before contract signing Water damage found

The water damage was discovered during the inspection, it does not say anywhere that she concealed anything from me.

Sorry, then I misunderstood the original post.

In principle, you are right, but of course it depends on the market situation in your area. In many parts of Germany, if the price was not already on the higher side before, not much would happen. Because then the seller would simply say that the next one is coming soon and the water damage doesn't bother them that much.

Has the seller already been contacted and what does she say? Of course, you can/should first report it to the insurance and see if they cover it. Then you can see whether it can otherwise be handled through a price reduction. But for that, you would also need to know how severe the damage is.

What kind of renovation do you have planned? A proper complete renovation? I don’t see huge problems with a relatively new water damage if everything is going to be redone anyway and the whole thing can still dry out in the core/shell condition and then will be rebuilt anyway. It’s not a half-timbered house. Does the house have wooden ceilings? The roof isn’t affected either. I understand that you don’t find this great now, but I think, looking at it soberly, it’s probably not such a big problem. Personally, I would talk to the seller and say, look, let’s have a professional check it out, and if they say it’s still fine, then it’s okay. At their expense or it will be offset in the sale. It doesn’t have to be a huge expert report. I think that’s how I would do it. A water damage that is years old, where it has been leaking for years and the substance of a house has been sustainably damaged (ceilings, roof, etc.), that would be different.

No complete renovation and definitely not tearing out the screed from the basement. But that is also stated in my initial description. It is about ending up stuck with this amount x of the additional renovation costs afterwards, and anyone who has once torn out the screed from the basement including the new drain pipes that are damaged during the removal plus disposal knows what I am talking about. The owner is trying to get every cent out of a six-figure sum. My problem is simply that walls are suddenly damp where no water has been standing.

If you have such serious concerns about damp walls, etc., then yes, you have to treat yourself to a professional. That’s just how it is. But with a six-figure sum, well-invested money.

If the owner tries to get every cent out of it, then despite the water, she will not reduce a single euro or accommodate in any other way.

You wrote that you want to do the pipes anyway. That’s why I assumed a possible complete renovation. From the pictures, it looks like everything needs to be redone anyway. Apparently, not much has been done since it was newly built in the 70s.