I didnt know that my sink was leaking making the woods under it wet which made it ideal for termites. When I check under the sink there were mud tubes and termites. The house/sink is made of concrete and the only wood was the cabinet under the sink. No wood is in contact with the soil. So my question is can a subterranean termite colony live without access to the soil? There were swarmers that got inside the house a few months back which I guess found the wet wood under the sink and started a colony. Is that even possible?
You should ask a professional, well established pest control company. I can tell you only about my experience in Florida that Subterranean termites can establish colonies by building mud tubes up the sides of concrete block, to reach wood inside your home. In Fl. A lot of the big companies use Termidor, which is injected into the ground surrounding your home. They treat your house every ten years and will offer a warranty if you pay about $125. Per year and they inspect your house yearly for signs of damage. What we call dry-wood termites fly into your house through openings and colonize after they drop their wings. Often they can be treated with a type of heat gun and other means if the infestation is localized. If they are all through your house they usually treat by tenting the entire house and gassing them.
I'm sure there are other opinions and treatments, esp. in different climates.