Underfloor heating leaking? Is moisture rising up the wall?

We had something similar on the ground floor. It was the outside water tap exactly on the outer wall of the room that let water through between the screed and the walls.

We had something similar on the ground floor. The outdoor faucet was exactly on the exterior wall of the room, which allowed water to pass between the screed and the walls.

The OP is talking about all 4 walls. @OP: it would be good if all questions were answered and more about the situation (house, floor plan, where the washing machine is located, where the water pipe runs, white tank, high groundwater, when it was first noticed, only on one wall, where first, …) were provided.

The OP is talking about all 4 walls.

Yes, it was the same with us on all four walls: water went under the screed and crept up all four walls.

Why is there actually no more from the TE? Reads everything but says nothing.:(
Why wait a whole half year anyway? And cracks look different from „water damage“.

Sorry for the late reply. I tried to make a sketch here. The basement wall of basement 2 is recessed slightly to the back, which I marked with the red line, as well as the door. It started at point 1 first; we had a large picture there, so only small changes were noticed. At point 2 there have been drywall panels standing since April, because I am finishing basement 1 and took a break due to the warm temperatures; they completely obscured the view and I only saw this today when I moved them away. Point 1 and 2 look like cracks but they are not; instead, the plaster is pushing out from the wall there, as you can see in the pictures, and point 3 has been visible since yesterday. At the other walls you don’t see any kind of cracks but early signs that the plaster is also pushing out, which you can also clearly see in the photo with the stairs, where it is visible in the initial phase. Point 5 is where our washing machine and dryer are located. The water pipes go directly there and the drain is also in the corner. Point 4 is where the hot water tank is and the pipes for the underfloor heating as well as the other water pipes go into the house there. I hope I was able to give you a better insight.

Best regards
TT

Turn off all the water consumers and look at the meter or take two photos a few minutes apart. We had a leak in the water pipe with water damage a year ago … you could see it on the meter, the small gear was turning very slowly.