#askU2 -Did  know  is being forced to accept unsafe drinking water [for the sake of their billionaire sponsor's DAPL investment]? 

This is substantiated by #askwarren Question #5. This was further substantiated by one of the issues (listed as 7) with the Lake Oahe Environmental Assessment in terms of the witholding of information from the Tribe(s) appearing in three reports, though the first one already obtained is the most reliable source by far. This was what was witheld, probably because there is still no spill response plan.

Dakota Pipeline Is Ready for Oil, Without Spill Response Plan for Standing Rock - InsideClimateNews

As for point #4, that such submergence of HDD tunnels for crude oil transport is illegal in countries that are major oil transport hubs such as Turkey (meaning they won't even entertain the notion of putting such a pipe under a drinking water source, -as it is illegal to install one under a freshwater source), -do we know better than this? Yes, yes we do. Or it wouldn't be the subject of countermanding leglislation in Montana:

"Bill would ban pipelines from crossing underneath rivers, lakes" -The Missoulian