jerry brown imposed the first mandatory water restrictions. snow supplies a third of the state's water. there's new that is california's snow level is at the lowest in 65 years. danielle nottingham reports. >> the sierra valley snowpack is usually at its high right now. the snow drought is apparent. >> we are standing on grass and should be standing on snow. >> reporter: there is no snow to measure at this key survey sight. >> this is the first year in measurements going back to 1942 where the snow course has been bare. >> reporter: water officials say 60% to 70% of the survey sites have no snow. the governor is taking unprecedented action to deal with the drought. >> i'm issuing an executive order. >> reporter: for the first time in california's history, the governor is imposing mandatory restrictions to reduce water use 25%. >> it's going to affect golf courses, people's lawns, universities campuses all sorts of institutions. >> reporter: the snowpack which supply as third of california's water plunged to an historic low. >> people should realize, we are in a new era. the idea of your nice green grass getting lots of water every day, that could be a thing of the pas