Will We Win Against The Previous Owner Of Our House?

We recently purchased a new house on December 2024. About a month after purchasing the septic alarm started going off. It turns out there is a major septic system issue that was not disclosed in the sale. When we had a company come out to empty it, we learned that the same exact company had been here before for the same issue and had written proof they informed the previous owner of the issue. We are looking at roughly a cost of 8-10 thousand if we were to repair the system. We are fairly certain we would win if we opt to repair the current system. My question comes in with the option to go to public sewage instead. Because we aren’t technically fixing the problem, would we still be able to sue for up to the cost of what the repair would cost us and put that towards the cost of going public? The cost of public lines will be closer to 20k so if we can contribute to that with money from the previous seller it would be a huge benefit.