Stayed up in Glencoe literally 2 months ago and these notices were everywhere. Same when we camped next to Loch Ness, Loch Lomond and in Cairngorms.

I've seen the 'private supply' notices but I've never seen them say that water should be treated first (nor have I ever had problems with not.) It's disappointing if they're starting to do this in a blanket fashion.

Not Scotland, but I've travelled a lot in Wales, and most, if not all, of the cottages we have rented have had these notices.