So I went to finally change my fuel filter (again, after initially thinking I had the incorrect fuel filter last time I attempted to change it), and when I went to loosen the water drain, it twisted right off with very little force.
It appears I now need to replace the entire water separator just to get a new lower cap. Perhaps in purchasing the whole unit, a new filter will come with it as well? GM Part 22937278
Moral of the story: Be very careful not to over-tighten your water drain plugs. I thought I had been extra careful on mine, but it appears the unit is more fragile than I would have expected.
It appears I now need to replace the entire water separator just to get a new lower cap. Perhaps in purchasing the whole unit, a new filter will come with it as well? GM Part 22937278
Moral of the story: Be very careful not to over-tighten your water drain plugs. I thought I had been extra careful on mine, but it appears the unit is more fragile than I would have expected.