Can anyone help with a work problem.
We run a small caravan site in Wales which has dual language signage.
One of them highlights the place where people should deposit their waste water.
The English part of the sign states ‘Waste Water’ and the original sign in Welsh read ‘Dwr Gwastaff’ which I considered correct.
We have now been given replacement signs which read ‘Gwastraff Dwr’.
I would appreciate your opinions on the correct wording.
I would be comfortable with ‘Gwastraff Dŵr’ - it works, though both are acceptable.
It is common, when discussing/labelling various bins and recycling receptacles to name them in such a way, for example…
Gwastraff gardd for the brown bin - garden waste
Gwastraff cyffredinol for the green bin - general waste
The same as in English, you could use both ‘Water Waste’ and ‘Waste Water’.
Hope this helps. 
Many Thanks Catrin.
I was thinking ‘Gwastraff Dwr’ would be an instruction to waste water rather than descriptive of the type of water.
Does the same go for the sign next to it that currently says ‘Dwr Yfed’ (Drinking Water) should it say ‘Yfed Dwr’?
Many Thanks
Dŵr yfed is fine. If it was me, I’d have gone for Dŵr i’w yfed, but that’s more of an alternative than a correction (Water for drinking vs. Drinking water).
Thanks robbruce
I agree the ‘water for drinking’ describes the type of water whereas ‘drinking water’ describes an action.
I guess going for consistency here is not going to work so we will settle for ‘Gwastraff Dwr’ and ‘Yfed Dwr’
many thanks for your replies