Here's the Franchise Tax Board's position:
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Generally, you must file an income tax return if you’re a resident, part-year resident, or nonresident and:
- Are required to file a federal return
- Receive income from a source in California
- Have income above a certain amount
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Assuming you are required to file a federal income tax return then the FTB's answer to your question is "Yes you do." Now if all you have is a California-sourced loss I suppose there's not much the FTB can do to you if they ever catch on, (penalties are usually based on reported taxable income), but I'd go ahead and file anyway just to memorialize and preserve those non-deductible losses, losses you're sure going to want to take if and when you sell the property.