We don't know what a lawyer for this area of expertise knows. The free consultation would be to find out if there is an avenue to pursue that he or she may instinctively know about because they do this for a living day in and day out. If you have no recourse than at least you will know you tried. I'm rooting for you trust me. Nobody needs a financial hit just after moving into a new home.
What if the last owners took down a tree and had the stump ground down and the vibration from the grinder cracked the pipe. They never got a permit and never made a disclosure on that form that your not supposed to lie on. What if they lied? Bingo! A lie survives the closing of title and you got their lying Azzes. Go Get 'Em! What if they discussed it with their realtor? Double Bing! Lawyer Up! If someone did something to you you're a victim if they didn't suck it up and go on with your life here. You've got a great story to tell at driveway neighborhood parties. If you need help we'll send Rocco & Vito over to help! (Just kidding about that part)
If it's not too personal could you mention how much the repair cost? It may or may not be worth it. If it's too personal I would understand that you may not want to talk about it. I wish you luck.
Don't forget to let us know the good $$$ news $$$ when you get it.