Connection for washing machine was forgotten in the new building

Hello,
we are currently in the final phase of our new construction. After various problems, we are actually on a good path to complete it soon.
Unfortunately, the washing machine connection in the utility room, which is listed in the [Bauleistungsbeschreibung], was forgotten.
We noticed it and reported it immediately. The room is fully tiled, painted, and the washbasin is installed.
Presumably, the [GU] will want to make the connection at the washbasin. Do we have to accept this or are we allowed to demand an installation within the wall?
Best regards

If the tiles are already on, you just noticed it a bit late. I wouldn’t put in much effort now because of that. Have a branch installed on the washbasin drain and drain there. The local 50mm or 75mm drain should easily manage that. In return, you can have a credit issued for the unperformed work – and I’ll throw in €150 as "compensation" – paid out to you for the pragmatic solution. Everything else is just unnecessary stress without significant added value.

For 150 euros, I would prefer the connection to be flush-mounted. I would not accept that for less than 500.

Thank you very much for your assessments!

I would prefer the connection to be flush-mounted for 150 euros. I wouldn't accept less than 500.

We probably can't really assess that properly in general. The question is how much wall would have to be chiseled out, whether there are any restrictions regarding the placement of the washing machine, etc. etc. Only the questioner can weigh that up for themselves. Listen to what the general contractor suggests, and maybe he will offer more than you expect just so you don't start a fuss now.

That is certainly the best idea for now. However, it is quite surprising that all the other craftsmen remained silent about it and we had to notice it ourselves.