First, did you know about the tanks when you bought the property? If so, I would ask your lawyer why they let you buy the property with out of compliance tanks. If someone was not honest with you I would follow that lead. Second, you do not know the site is clean until the tanks are out. As an Environmental Engineer I have been on site for the removal of dozens of USTs. I was responsible for directing the tank removal contractors, sampling the soil, completing closure reports, and working with the state to determine clean-up plans if the sample came up dirty. I can tell you that very few tanks come up “clean”. Even if there are not holes in the tank many get overfilled at some point in their life. Pipe connections are also often points of leaks. I would recommend getting a competent contractor to remove the tanks. The contractor should screen the soil as it is removed with a PID or other similar equipment that will detect volatile organics in the soil. You should be prepared to dig out a little extra soil to get to clean soil if you do come across a small leak. It can be cheaper to dig out all dirty soil when you take out the tank and get rid of the contaminated soil at a certified disposal location. That way you can document closure soon rather than going through the installation of monitoring wells and sampling for years. Anything you do you should talk to a state regulator before you begin and share your plans with them before you start. Get their approval before you start. Make sure your contractor does not cut corners. You do not want to go primarily on low bid. Make sure they have positive references. If you go in with the right attitude and let the state know that you want to do the right thing, my experience is that the state with work with you to make things right. Good luck.