All About Septic Systems

All About Septic Systems




Submitted by: Michael Del Greco
Accurate Inspections, Inc



Septic systems are a "dirty" topic, but one that should at least be understood by homeowners. Here's an overview of how your septic system operates as well as preventative maintenance steps you can implement.

The Way A Typical Residential System Works

1. The waste from the house goes into the tank and the anaerobiotic bacteria breaks down approximately 65% to 70% of the solid waste. Anaerobiotic bacteria develop when air is not present (Most common type system). Aerobic bacteria develop in the presence of air and would break down 90% to 95% of the solid waste.


2. The liquid waste is called effluent and normally goes into the leaching fields at the same rate that you use the system. Example: If five gallons of waste goes into the tank (liquids and solids), five gallons of effluent goes into the leaching fields.


3. The effluent goes into a distribution box that is installed level so that each leaching bed receives the same amount of effluent.


4. When the effluent goes into the leaching fields it is absorbed by the soil.


The Parts of a Septic System

1. Concrete or steel tank (1,000 gallon is typical)

a. With maintenance, a concrete tank will typically last 40 to 50 years.

b. Steel tanks typically last 20 to 30 years. These were last installed in the middle 1960s.)

c. The tank has inlet and outlet pipes and baffles to separate scum/grease from the effluent that goes into the leaching fields.


2. Leaching fields

a. Stone beds with a perforated pie (in most cases).

b. Sand mounds are only needed if the soil does not "perk" (see "perk" explanation below).


Maintenance Suggestions

1. A septic tank should be pumped out every 24 to 36 months (average family of four people).


2. A clean out should be installed if there is none.


Other Information

1. Do not use a garbage disposal when you have a septic system or cess pool because it will dilute the biological farm (deplete bacteria activity). Note: Photographic chemicals, paint or grease that are disposed into the system will tend to shorten the life of the septic system.


2. "Perkability" is the rate at which the soil will absorb water. Check with the local authorities for the acceptable rate. You should test about eight times or until the readings become stable. Note: Perkability tests are performed before a system can be installed.


3. The tighter the soil is, the shorter the life of the leaching fields and the less the soil will "perk".


4. Leaching fields are not to be below 3'.


5. Cost for a new septic system is approximately several thousand dollars depending on the conditions. An elevated sand mound could be an additional $3,000 to $5,000.


6. Adding yeast to a septic tank to help the bacteria activity is a myth. Human waste will produce ample amounts of anaerobiotic bacteria.



Information provided by Michael Del Greco, New Jersey Home Inspector Lic. GI 0121, American Society of Home Inspectors Member 102273, Pesident of Accurate Inspections, Inc. A West Paterson New Jersey Home Inspection firm.