Legal Question in Real Estate Law in California

Re: Zero-Lot Line Home

There are only three appellate cases in California that come up in a WestLaw search for the phrase "zero lot line," and two of them are unpublished, meaning they cannot be cited and do not really reflect the law on that point. None of the three sheds light on your question, either.

My guess is that zero-lot-line walls are covered by local ordinance and/or zoning regulations, private agreements (such as easements) between the "original" neighbors which "run with the land," or CC&R's in the case of planned developments.

I found more cases when searching the term "party wall." This is something different than a zero-lot-line wall, of course; a party wall stands (supposedly, at least) partly on the land of each neighbor, whether or not used by both. A zero-lot-line wall would be entirely on the land of one neighbor, but with no space. As with zero-lot-line walls, party walls seem to be based on private agreements (contracts), and in your case I suggest that you do research to determine whether there is an agreement reflected in recorded documents covering the properties or, perhaps, in a title report prepared when one or the other of the properties was sold or (re)financed.