The size of the drain field is determined by how well the ground absorbs water. In places where the ground is hard clay that absorbs water very slowly, the drain field has to be much bigger. A septic system is normally powered by nothing but gravity.he size of the drain field is determined by how well the ground absorbs water. In places where the ground is hard clay that absorbs water very slowly, the drain field has to be much bigger. A septic system is normally powered by nothing but gravity.
Filed Under: Tech & Science, mental health. Every year, about 42.5 million American adults (or 18.2 percent of the total adult population in the United States) suffers from some mental illness, enduring conditions such as depression, bipolar disorder or schizophrenia, statistics released Friday reveal.
1 Approximately 1 in 25 adults in the U.S.â10 million, or 4.2%âexperiences a serious mental illness in a given year that substantially interferes with or limits one or more major life activities.2.  Approximately 1 in 5 youth aged 13â18 (21.4%) experiences a severe mental disorder at some point during their life.