As far as I know, Furnace Creek is an oasis, and its golf course is irrigated by non-potable groundwater from local springs.
Water Conservation at The Oasis: https://www.oasisatdeathvalley.com/who-we-are/sustainability...
Hydrogeology of Lower Amargosa Valley (see Fig. 1 in report): https://pubs.er.usgs.gov/publication/sir20185151