Nearly 20 million homes encompassing almost 30 percent of the U.S. population dispose of their sewer and wastewater through an on-site disposal system.  Fifty-four percent of the population in North Carolina and 38 percent of the people living in Indiana use these systems.

One of the major differences between owning an urban or suburban home and owning a rural home is that in a rural home you must become more self-sufficient and self-reliant.  Waste disposal — trash, sewage, and wastewater — is one of the primary concerns of a rural homeowner.

The most common way to dispose of sewage and wastewater in rural homes is through the use of a septic tank.  Some 85 percent of the on-site disposal systems in the U.S. are septic tanks.

A septic tank system contains two major components, a holding or septic tank and the absorption field.   The holding tank is usually made of concrete, fiberglass or plastic.  Therefore it is resistant to corrosion and decay.

While typically designed to hold 1,000 gallons of liquid, the size of the tank varies depending upon the number of bedrooms in the home.  The purpose of the holding or septic tank is to separate the solids from the liquids.


The solids in the form of sludge, which collects on the bottom of the tank, and scum, which floats on the tops of the water, remain in the tank and are pumped out periodically.

The wastewater is passed on to the absorption field through a connecting pipe.  The absorption field is also known as the soil drain field, the nitrification field or the soil absorption field.  The absorption field is a series of underground perforated pipes, usually, but not always, connected in a closed loop system.

The perforated pipes ensure that the wastewater can reach the entire absorption field.  The absorption field treats the wastewater through an aerobic digestion process and filters out the remaining impurities (germs and chemicals) before the wastewater returns to the groundwater system.

Sewage effluent coming out of the holding tank is a cloudy liquid that still contains many disease-causing germs and pollutants.  When this water flows into the perforated pipe in the absorption field, the sewage effluent exits through the holes in the pipe and trickles through the gravel where it is stored until it is absorbed by the soil.  In some systems, subsurface chambers store the effluent.  As the effluent enters and flows through the unsaturated soil, many of the bacteria that can cause diseases are filtered out.  Some of the other smaller germs, such as viruses, are trapped and held by the soil molecules (absorbed) until they die.  The soil can also retain certain nutrients such as phosphorus and forms of nitrogen.


Put all of the wastewaters from the home into the septic tank.  This includes all sinks, bath, shower, washing machine and dishwasher wastewaters, in addition to the toilet flushings.  Any of these waters can contain disease-causing germs or environmental pollutants.  Direct roof drains, basement sump pump drains and other rainwater or surface water drainage systems away from the absorption field.  Flooding of the absorption field with excessive water will keep the soil from naturally cleansing the wastewater, leading to groundwater pollution.

Do not use caustic drain openers for a clogged drain.  Instead use boiling water or a drain snake to free up clogs.  Clean your toilet, sinks, shower and tubs with a mild detergent or baking soda rather than the stronger and potentially system-damaging commercial bathroom cleaners.

NEVER use your septic tank system as a trash can.  Be especially sure to avoid putting excessive amounts of grease, disposable diapers, anything plastic, latex paint, pesticides, solvents, oven cleaners, degreasers or any hazardous chemicals into your system.


In summary, care should be taken to not dispose of items into the system that will destroy the natural digestion process, or over-tax the drain field with excessive water.  Regularly pump out (every 2-3 years) the sludge in the holding tank.  If you adhere to these few simple rules, then your septic tank system will prove to be a safe and economical on-site method for disposing of your rural home wastewater.

Mohave County Dept. of Health & Social Services
Environmental Health Division, Lake Havasu City Office
2001 College Dr.    928/453-0712