You could search the address to see what other listings say, or you could call an agent and have her/him run a search for you. When an agent enters a listing into the MLS, they have to indicate if the unit is a condo or coop, but as you've found there may be mistakes sometimes. Generally coop fees include all of the utilities as well as the taxes. But depending on which sites you are using to search, you may or may not have access to that information. Let me know if I can help.