Water leaking from my ceiling.  Who pays repair costs?

I live in a condo and I noticed I had a water stain on my ceiling-figured it was the toilet leaking for the upstairs bathroom had a plumber come out. He evaluated to find it was not the toiled but after opening the ceiling its a leak in the elbow joint in sprinkler pipe. Would this be something the association would be responsible for? The main shut off is in another unit.  Massachusetts