The swimming hole and river that flows behind the El Questro campground is also the Pentecost River, but it's safe to swim there, just look out for slippery rocks(hubby slipped and broke his thumb first day there
) As Christian said, you wouldn't swim in the section where it joins the Chamberlain River. Big salties in there.
We also swam in Emma Gorge but it's FREEZING cold(look for the hot spring up to the right behind the rock), El Questro Gorge(the walk to the very end is really worthwhile) and the magnificently warm and relaxing Zebedee Springs. Some of the other swimming holes on the property were still closed when we were there in June 2011.
Loved El Questro!
Trevor - don't know if you'll be heading up to the Mitchell Plateau, but we camped at the King Edward River site and the ranger told us we could drink the water straight out of the river there, which we did for four days with no dodgy belly after effects. Maybe we were just lucky, but it tasted great!
We also filled up from the tap at Mt Barnett and at El Questro with no problems.
Cheers
Karen