Septic tanks are privately-owned enclosed sewage systems that are most often used in rural and new suburban areas. There are many different types, but they all use some kind of enclosure and filtration system and are emptied by a private company.

As climate change impacts sea levels, water tables, average temperatures, and average rainfall, previous standards for septic tank systems are no longer adequate. About 20% of Americans use septic tanks, and over half of those have been compromised in recent years due to changing weather patterns and groundwater levels.