How Does a Septic System Work? Septic systems are underground wastewater treatment structures that use nature and technology to treat wastewater from household plumbing. If you’re new to owning one, you’re probably wondering how septic systems work. In this article, we’ll explain common types of septic systems and how they typically function so you can take better care of yours. Types of Septic Systems Septic systems usually consist of a septic tank and a drainfield aka leach f...