The holder should be robust enough, because it needs to hold 7m of hose ended with water pump. The diameter is set for 1" hose. For different hose feel free to modify FreeCAD design.  Itis recomended to have bigger hole and use rubber around hose. The groove in a model is purposed for rope or cable.

There is needed 2 screws M6 and 2 M6 matters.

I have used ABS because it is stable in wet environment. PETG could be also used.

Infill was set to 30%, every 10th layer was solid,

 3 perimeters