^ Exactly right.
There's no way that the individual unit owner should be responsible for in-wall plumbing. That's common property and is under the management of the corporation. Your condo must have a maintenance number? Or at the very least the condo management company. I'd go so far as to say that there may even be trouble if you go it alone.
I had a leak (behind the shower) and it was the corporation who handled everything related to it, including arranging the plumber and rebuilding the bathroom below my (where the water leaked and caused big damage).
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