It may be the buyer's responsibility to look into the zoning regulations before attempting to purchase any property, but it's also wise for the seller to be very aware of what the zoning looks like in advance. This can help to avoid disputes.
Remember, the issue may not be as clear-cut as someone trying to buy a building in a residential area for commercial use.
For instance, one party may be looking to buy the property to turn it into a duplex. That person intends to live in one apartment and rent the other side out, thereby covering the cost of the mortgage with the rent payments. This may be the only way that the person can afford to buy that property at the asking price.
However, it may then turn out that the zoning is only set up for single family homes. If this information comes to light after the potential buyer has made an offer and it's been accepted, he or she may then want to get out of the sale. Even if the person still wanted to buy the property, it is suddenly not affordable due to the zoning.
As you can imagine, this can really throw a wrench into a sale and result in that sale not going through. Sellers may feel frustrated, assuming buyers should look into the zoning themselves, but it's clear that understanding the legal situation more thoroughly on both sides could have helped avoid the issue and the dispute because the offer never would have been made.
With any real estate dispute, it's crucial for both parties to know what role the contract plays, what laws and regulations are in place and what rights they have.
Source: American Bar Association, "12 Ways to Foul Up a Real Estate Transaction," Evan L. Loeffler, accessed Sep. 07, 2017