Infiltration not possible - what to do?

Well then, just direct everything into the sewer. You can always still consider a cistern.

Well then, just drain everything into the sewage canal. You can still consider the cistern.

Well, maybe you should first secure yourself with a written confirmation! ;)

The infiltration and approval of the soakaway is normally indeed the responsibility of the lower water authority.
However, if you have no requirements in this regard, then check that and do everything else in writing.

There are municipalities that require infiltration on their own property, others again require connection to the sewer system.... that there are some who don’t care at all is hard for me to imagine. But who knows....

Discharging into the sewage system is not allowed because the village's sewer system is already completely overloaded.