The concept of plumbing and sewage disposal is older than some people might think. Even the ancient Romans used plumbing, and they coated those pipes with lead. The Roman word for “lead” is, in fact, where we get the modern word “plumbing” and the atomic symbol for lead on the Periodic Table. Most houses in the United States today are connected to public utilities for receiving clean water and disposing of dirty water to processing plants. But about 25% of American properties are too far away from these pubic utilities, so they make use of self-contained systems instead: septic tanks…