Using Ikea dirigera as z-wave repeater if possible or any other tips?

What makes you think that the Ikea Dirigera Hub can be used as a range extender for the Aeotec Water Sensor?
The Ikea Dirigera Hub isn’t supported by Homey and it uses Zigbee as wireless protocol. So no, it will not work at all.

The Aeotec Range Extender 7 could be a possibility.