Money..Yeah but CA has known about this issue since the early 80's. I know that there were plans back that far for a pipeline from Alaska to norther CA - it was just too cost prohibitive back then. I still don't see why treated water can't be piped somewhere.....Hell even if it is just for irrigation. I have always wondered if the water was back up to where it generally is with some of the reservoirs would it be enough to impact the weather patterns in parts of the state.
We recently voted for 7 billion in infrastructure improvements.
http://ballotpedia.org/California_Proposition_1,_Water_Bond_(2014)