Back in 2004 State Water Resources Control Board decided to charge a fee for monitoring the agency's water rights holders.
The case Californian Farm Bureau Federation vs. State Water Resources Control Board has gone to the California's appeals and supreme courts and then sent back to the Sacramento Superior Court.
The argument is over whether or not the SWRCB can call this a fee or a tax, which would require a two-thirds vote. There is also the argument about pre-1914 water rights holders that were not being charged. The decision on this