I’m paranoid.The real question is: why do you feel the need to find the septic tank?
Does it need to be cleaned out again? Do you have a drain problem you think?
That is possible. Then again, my house was built in the 1940s. We didn’t have indoor plumbing until the 60s, but I don’t know who laid the pipe, so it’s all an unknown.Depending on your state laws, a plat marking your septic is likely filed with your state health department. In Arkansas, unless you are building on a plot of land larger than 10 acres (in which case you are exempt), then you are required to file for a septic permit. My house was built in the late 80s. If I didn't know where my septic was located, I could look up the permit application which should show the tank and location of the field lines.