We consistently recommend a video scoping of the main sewer line going out of the house to make sure it is draining properly and a test of the radon (radioactive gas) levels in the home. We also heavily push for a meth screening. In the state of Colorado a house can be considered a meth lab if someone has smoked in the house only a few times. To clean the house of meth it can be $20k-100k. That is a bill that you do not want to get stuck with! If the home is on a well and septic system, you’ll want to evaluate the quality and quantity of water you can expect from the well and the septic system. Beyond this, there are many other issues that you may want specialized inspectors to look at on a case by case basis.