Legal Question in Real Estate Law in California

You have to be able to prove that either the seller or the broker or both knew or legally was obligated to know of the change, and failed to disclose it. The MLS information is not legally reliable, because it is always accompanied by the disclaimer that it is "believed to be reliable but not guaranteed." That means it was up to you to verify anything in it that was material to your decision to buy or not buy and what to pay. So unless they withheld information known or legally deemed to be known to them, you have no case. It's no different than if there was an unknown structural defect in the house that an inspection would have revealed but you closed without an inspection. Only if it was known and not disclosed would you have a case.

While generally agreeing with Mr. McCormick, I'd add that an important factor might be whether the school-district change was something the seller were likely to know about. If the seller(s) was/were parents of school-age children who lived in the house, the likelihood that they knew or should have known is greater and the chances of a successful lawsuit are greater. If the seller was an elderly bachelor, or an absentee owner, I'd say it's very unlikely the seller had any knowledge of the about-to-occur change. Other factors might include the amount of publicity attending the change. Some school-boundary changes are very hotly contested and get wide press coverage, while others are little known beyond the affected families. Finally, you should verify that your kids will be obliged to attend the new school -- in some communities, there is a certain amount of permitted choice and mobility in where kids attend school.