Water was usually not a problem - the California Gold Country has plenty of streams and rivers. During the drier times, miners had to wait for enough flow to "wash dirt" - the method used to expose gold, but there was always enough to drink.

Miners spent a lot of time hunting. I co-edited the letters of the Grosh Brothers - placer miners in the California Gold Rush. They described how two of their group would wash dirt while one or two others would go hunting. They would then share everything that each was able to produce during the day - food and gold. That was the typical approach for the first miners in the Gold Country.

There were also those who farmed. The Grosh Brothers gave up mining at some points and took up agriculture, but the lure of gold always brought them back (and they eventually died in the effort). There was also a great deal imported to California. Ships were repeatedly making the trip to Mexico and South American, bringing back passengers (and the mail!), but also a great deal of food grown in those areas. Costs were inflated in Gold Rush-era California, but acquiring food was not difficult.

As the Gold Rush went through its cycle of initial rush, depletion of gold, and then retreat from the Gold Country, infrastructure improved and more people were involved in agriculture, exploiting the rich natural resources of Northern California, which continue to feed the nation. Acquiring food was never that big of a problem; the real question was a matter of distribution and cost, but since the first years were "flush" with gold, money was no object.