Its no wonder this forum has gone to the dogs. Someone asks a perfectly reasonable question and gets a snippet of information as one of the replies. Then a number of other people chime in with opinions, not facts, about how that can't really be true because they know loads of people who do just that. I know loads of people who break the speed limit; that doesn't mean it's OK, they just got away with it.
I have a statement in my deeds that says I can't extract water from the river. I've no idea what the penalty would be, if any. I do know people, personally, (not whispers, or someone a friend knows), who have been visited by the gendarmerie with regard to garden fires; we're supposed to get a "note" from the mairie and approval from the pompiers (or is it the other way round?); no-one does... usually. All wells are now meant to be registered at the Mairie; that's because extracting water affects the water table. Who, in heaven's name is going to police that one when they can't keep track of non-complying fosses? Just because you've had a well for 12 years (as we have) doesn't give you any special rights, you've simply ignored the restrictions and got away with it. As the secretary at our mairie once said when I asked about having a garden fire, "We live in the country, we do as we like!"
River water may be fine when you analyse it but what about a day later when a dead cow or a run-off of nitrates has got into the water?
We could go on for ages with theories and extended myths. Let the guy use the water if he wants. Perhaps he'll let us know what happens; prison or hospital bed.
Oh, this forum; on its last legs. Someone chuck it in the river.
It's difficult to say what my wife does...
She sells seashells on the seashore.