Running Factorio 0.17.66
Not using RSO.
Using 21/32 sizing.

The mod option 'Water at dead ends' is checked, as are all of the 'Dead end ...' options, but I have revealed the map out past 100 chunks, and there are no water patches. Lots of normal resources, quite a bit of green wood, two extra oil patches and 1 extra uranium patch, but no water. Is it really meant to be scarcer than oil and uranium? Every dead end seems to have some resource.

Update: Nevermind, I hadn't realised that the green wood was in water. I hadn't researched the mangrove harvester yet, so didn't go to look at then green wood sources.