W2 Box 20 Locality Name

I live and work in California. IIn my W2, in Box 18, it says "CASDI" and then an amount. Now TurboTax wants me to fill out Locality in Box 20, but my W2 does not have it. 

What should I enter in Box 20 - the locality where I live, or where I work, or where my employer head office address is? Do I put a zip code in the locality, or county or city name?