I have to guess here you did not have an attorney for your purchase. The thought that a competent attorney would let their client proceed in this type of situation is pretty horrible and doubtful.
The City will file a lien based on the past due water bill. It typically takes a long time for the City to enforce that lien. They don't want your property/Condo building, they want the money. How occupied or empty is this building? Depending on occupancy the City may or may not terminate water service.
An important factor is whether the developer properly notified Water that the building went Condo. If Water was properly notified and has the property listed as a Condo building, you may be in luck. You should be able to pay your portion of the outstanding bill, get an FPC from Water and record your deed in your name. If the developer did not notify Water, it will be a long battle.
Any and all legal recordings will have to be dealt with by you and your attorney at your cost. It is highly unlikely anyone else will go to the time and expense to do it for you.