We were there December 2013 and noticed the sign also---First of all, it is a sign from at least 2012. Second, we saw (mainland USA) Natural Park Service employees fill their water bottles and drinking directly from the outside spigot/fountain. They knew nothing about the old sign warning of water problems. They said the water was fine! We did prefer to filter our water regardless. We took an extra collapsible 5 gal water jug and have our own portable hand pump water filter (MSR Miniworks EX Microfilter), and after filling their 5 gal jug with tap water, we used that as our water to filter into our own 5 gal jug, or our own water bottles. Worked very well. Tasted great!