Septic Tanks

Underground septic systems have been in use since the 1870s. Now, nearly one-third of all homes in the U.S. use them for household wastewater management. Septic tanks and systems, if used properly, are the most efficient method of waste management.

"Properly" is the key word, however. A household septic tank system can last upwards of 50 years, but that lifetime can be drastically shortened if improperly used. It's important to understand just how a septic system works, and for many people that means changing their flush-and-forget mindset.


How Septic Tanks Work

A septic tank operates similarly to our own digestive system in that the active ingredients are the microbes that populate our own intestines. These bacteria are anaerobic-they do not need oxygen to do their job. In ideal conditions, a thriving group of microbes will break down all of the waste provided to them quickly and quietly, albeit with the occasional burp of methane gas.

Septic tanks are two-part affairs with an inlet pipe from the house at one end and an outlet pipe to the leach field at the other. After waste enters the first part of the tank, it settles out. The lighter components of the waste continue on to the second part of the tank. As this area is less disturbed by incoming waste, finer particles can settle out. The settled particles in both tanks are then digested and broken down by the self-regulating population of anaerobic bacteria in the tank.

Septic Tank: Waste Secretion

The average 3-person family home employing a septic tank system will discharge approximately 200 to 300 gallons of water, in addition to wastes, into their septic system every day. About 40 percent comes from toilets, 25 percent from washing machines, 20 percent from showers or baths, and 15 percent from sinks. Most septic systems will handle this load without problems. Where problems occur is when people introduce other materials into the system.

Substances to Avoid With a Septic Tank

Cooking oils and fats can reduce the efficiency of septic systems. Also, the introduction of cleansers and other toxic chemicals can kill the very microbes that keep the system functioning. It's crucial that only cleansers specifically formulated to be compatible with septic systems be used.

Installing a Septic Tank: Hiring a Professional is Essential

A professional contractor should always be used when installing a new septic tank and septic system. They will test the soil and conduct permeability tests to make sure that the soil is capable of supporting the system, as well as determine what type of system will work best in those conditions.

For further information on septic tanks see the following article from Residential Septic Tanks.