Legal Question in Real Estate Law in California

You have not provided enough information about the agreement between you for them to use the buildings, to answer the question.

While, as Mr. McCormick says, more information would be helpful, maybe I can give you some basic pointers without knowing the details.

Storage of this kind comes under the legal topic heading of "bailments," although California statutes for some reason calls bailments "deposits." That sounds more to me like putting money in the bank or making a down-payment on real estate than giving physical property to someone else for safekeeping, but we have to live with the statutes as they're written.

"Deposits" are subdivided into several categories, depending upon whether they start out accidentally (like when your plumber forgetfully leaves his toolbox in your basement) or intentionally, and whether they are "gratuitous" (you don't charge and don't expect to make a profit) or "for hire" or "storage" (when you charge a storage fee or expect to sell goods left with you on consignment). There are a few other subcategories.

Deposits are covered in the Civil Code, sections 1813 to 1881.2. Assuming you are charging something, you'd be governed largely by sections 1851 to 1856. Section 1854 covers termination of deposits that are "for hire" or "storage" -- it reads "In the absence of an agreement as to the length of time during which a deposit is to continue, it may be terminated by the depositor at any time, and by the depositary (you) upon reasonable notice."

So, I'd say give "reasonable notice" to the other person. What's reasonable? I'd guess it depends upon the distance the guy has to come to get his stuff, how much and how bulky it is, how long it oughta take for him to find another place, and other factors. Maybe a week, maybe a month, maybe more or less. You also have to give reasonable access; you can't change the locks after giving notice, for example. Also, notice must be given in a way that it is likely to reach him.

If the depositor doesn't pick up his stuff or make arrangements with you within a reasonable time, then give him a second notice to the effect that his storage rights are canceled and that you'll soon be disposing of the stuff. After some time, then, you'll be entitled to dispose of the stored property, which also must be done in a "commercially reasonable" manner. If it's junk, take it to the dump. If it has value, sell it via eBay, classified ads, flea markets, dealers, pawn shops or whatever makes sense in the real world. Compensate yourself for your expenses, but any excess cash belongs to the former depositor and you need to turn it over to him, with an accounting.