Marin County seems to have made dry, powdered/flake form of Lye a controlled substance: very difficult to obtain. I think the prohibition has something to do with lye being a component in the Meth Recipie. You can still find lye in liquid forms like Liquid Draino at hardware stores, but I don't trust that in a food recipie.
Lye is also a key ingredient in the candle making / soap making process. If you perform a general web search, you'll find places in Timbuktu that can ship lie to your door...
But to find some place *local,* I went to Google Maps and queried, "candle making" and found an "almost local" studio in Point Richmond that sells "food grade" lye in one pound containers.