Quote Originally Posted by hagare View Post
is checking manually the only way to know if a house is up for sale?

If you mean has a chance of being available you can only know by looking through the wards from the NPC who teleports you in or being IN the ward with the available and looking at the map. If you're talking about being purchasable as in the random timer has expired and you can just walk up and buy it, you can only find that out by clicking the placard and attempting to buy it.