Southern Nevada gets almost 90% of its water from the Colorado River. Southern California also gets substantial water from the Colorado, which has the unenviable status of being the most litigated river in the world. The problem for Nevada is that it agreed to a small apportionment of Colorado River water back when their population was tiny. Southern Nevada gets 0.3 Million Acre Feet a Year (MAFY) while California gets a princely 4.4. This was a big mistake in the water wars for Nevada.