How much should you charge to tile a shower per sq foot in California?

There's no rule about this because there are too many variables - size of the shower, Plumbing issues, what sort of shower pan is needed (or existing), type of tile and grout, what sort of surface to which the tile will be applied (or does cement board or waterproofing membrane need to be installed first), straight lay or patterned, deco pieces or accessories, do the existing shower walls need to be demo'd, fees for disposal of waste, transport of materials, necessary supplies, etc. The square foot charge could range anywhere from $5 to $25 per square foot for just the tile & grout alone. Other charges will probably be necessary, but that's impossible to estimate in general; they must be based on the specific needs of the project.

If you are contracting the project to be done in your home, your best bet is to get three estimates from tile installers. Question them about their methods and warranties, and then decide which fits best for your needs.

If you're a tile installer just getting started and don't know what to charge, I'd suggest you calculate your time (including set up, clean up, down time, and so on) for the specific needs of the project, and figure a fair hourly rate to come up with a total, then break it down for a square foot charge.