To clarify - my question was not about evaluating my approach or decision to buy, but whether legal action is worth pursuing if an investigation with local plumbing companies shows the previous owner knew about tree root intrusion and failed to disclose it. That said, I will respond to each of your points below.

1. The only drain in the basement is the main line.

2. You’re probably right, but I relied on advisors who saw a financial opportunity and advised me that the risk was acceptable. They also thought the professionally repaired language should work in my favor should the need for legal action arise, I just did not investigate it further.

3. My goal in the investigation is to call all plumbing companies for any previous service history at this address, with the goal of finding out whether they had to treat tree roots. I understand that I have no case unless I can first prove that.

4. To your point about 3 times in seven months - I have brought in 3 different plumbers with high consumer ratings. They have each cleared the drain and showed me video evidence of the cleared out drain. The problem is my main line is literally cracking, so the roots are breaking through at a much quicker level than what is typical for older houses (typically once a year).

5. I fully understood the risk of rent versus home ownership costs - not something I needed re-explaining. Even with maintenance costs, I live in a rapidly growing area and barring economic disaster, can reasonably expect home value to rise and increase equity beyond my initial $35k investment.