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Woman pouring chemicals in toilet

We civilized humans started out by defecating into a hole in the ground (outhouse), then discovered we could float our turds out to the hole using water and never have to leave the house. However, one of the unfortunate problems with septic systems is, like outhouses, they pollute our groundwater.

There are currently 22 million septic system sites in the United States, serving one fourth to one third of the US population. They are leaching contaminants such as bacteria, viruses, nitrates, phosphates, chlorides, and organic compounds such as trichloroethylene into the environment. An EPA study of chemicals in septic tanks found toluene, methylene chloride, benzene, chloroform, and other volatile synthetic organic compounds related to home chemical use, many of them cancer-causing.3 Between 820 and 1,460 billion gallons of this contaminated water are discharged per year to our shallowest aquifers.4 In the US, septic tanks are reported as a source of ground water contamination more than any other source. Forty-six states cite septic systems as sources of groundwater pollution; nine of these reported them to be the primary source of groundwater contamination in their state (see Figures 5.9 and 5.10).5

The word "septic" comes from the Greek "septikos" which means "to make putrid." Today it still means "causing putrefaction," putrefaction being "the decomposition of organic matter resulting in the formation of foul-smelling products" (see Webster). Septic systems are not designed to destroy human pathogens that may be in the human waste that enters the septic tank. Instead, septic systems are designed to collect human wastewater, settle out the solids, and anaerobically digest them to some extent, leaching the effluent into the ground. Therefore, septic systems can be highly pathogenic, allowing the transmission of disease-causing bacteria, viruses, protozoa, and intestinal parasites through the system.

Graph of sources of groundwater contamination in the United States

One of the main concerns associated with septic systems is the problem of human population density. Too many septic systems in any given area will overload the soil's natural purification systems and allow large amounts of wastewater to contaminate the underlying watertable. A density of more than forty household septic systems per square mile will cause an area to become a likely target for subsurface contamination, according to the EPA.6

Toxic synthetic organic chemicals are commonly released into the environment from septic systems because people dump toxic chemicals down their drains. The chemicals are found in pesticides, paint and coating products, toilet cleaners, drain cleaners, disinfectants, laundry solvents, antifreeze, rust proofers, septic tank and cesspool cleaners, and many other cleaning solutions. In fact, over 400,000 gallons of septic tank cleaner liquids containing synthetic organic chemicals were used in one year by the residents of Long Island alone. Furthermore, some synthetic organic chemicals can corrode pipes, thereby causing heavy metals to enter septic systems.7

In many cases, people who have septic tanks are forced to connect to sewage lines when the lines are made available to them. A US Supreme Court case in 1992 reviewed a situation whereby town members in New Hampshire had been forced to connect to a sewage line that simply discharged untreated, raw sewage into the Connecticut River, and had done so for 57 years. Despite the crude method of sewage disposal, state law required properties within 100 feet of the town sewer system to connect to it from the time it was built in 1932. This barbaric sewage disposal system apparently continued to operate until 1989, when state and federal sewage treatment laws forced a stop to the dumping of raw sewage into the river.8

Source: The Humanure Handbook. Jenkins Publishing, PO Box 607, Grove City, PA 16127. To order, phone: 1-800-639-4099.

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weblife.org | library | Humanure Handbook | Chapter 5: Ground Water Pollution From Septic Systems