Unincorporated areas use TLMA Building & Safety. Incorporated cities (Riverside, Corona, Moreno Valley, Temecula, etc.) operate independent permit desks. Desert and mountain overlays may add structural and fire-safety review.
How this fits with the state
The state authority here is California Contractors State License Board. The county file does not replace that — it adds the permit office, local overlays, and the actual filing path.