washing up water on plants

I save the cool water before it’s warm enough to wash up…(if you follow me). I sometimes use the used washing up water but I am using it on the flowers outside.

Yes, I do it regularly in warm weather.
Personally, I use very little washing-up liquid unless things are particularly greasy, but OH is the opposite. It all goes on the plants, whichever of us has washed up, and the plants all seem fine.