General Septic System Information

1. What Do Septic Systems Do?

2. How Does a Septic System Work?

3. How Is Sewage Treated In The Septic System?

4. What Is Meant by a Septic System Failure?

5. Why Do Septic Systems Fail?

6. What Are Some Signs of a Septic System Failure?

 

Septic Tank Pumping and Maintenance

1. How often should my septic tank be inspected?

2. Why is it important that I have my septic tank pumped?

3. How often should I have my septic tank pumped?

4. I heard I shouldn't flush toilet paper into my septic system. Is this true?

5. I have seen ads for septic additives that claim I don't need to have my spetic tank pumped if I use their product. Do these really work and are they a good idea?

 

General Septic System Information

 

1. What Do Septic Systems Do?

    

   Septic systems safely recycle wastewater back into the natural environment and thus protect the environment and human health.  Wastewater treatment by septic systems is done as well as, or better than, municipal treatment systems at a reasonable cost when they are properly designed, installed, operated, and maintained.

2. How Does a Septic System Work?

    

   In a typical septic sytem, also known as an On-Site Sewage Facility (OSSF), all wastewater is mixed, treated, and dispersed by a single system.  Common septic systems all have three basic components: plumbing that collects the wastewater and delivers it to the treatment system; the septic tank, which is a solid, water-tight tank (or series of tanks) that receives the wastewater and then seperates the solids from the liquids; and a soil treatment area (drainfield) that is usually a network of perforated pipes surrounded by small rocks and soil that receives the liquid from the septic tank.  The waste is naturally treated and decomposed by bacteria in both the septic tank and within the soil treatment area.

3. How Is Sewage Treated In The Septic System?

    

   In typical septic systems the raw sewage is collected by the plumbing in the home and delivered to the septic tank. In the septic tank the light solids float to the top, forming a scum layer, and the heavy solids sink to the bottom, forming sludge. The organic solids such as food particles and human waste are broken down (decomposed) by millions of naturally occurring bacteria. In regular septic tanks the bacteria do not require oxygen (anaerobic) while in systems with aerobic tanks, the bacteria require air to live.

   The septic tank then delivers the partially treated liquids (effluent) to the soil treatment area (drainfield). The effluent contains pathogens (disease-causing organisms), nutrients, chemicals, and some fine solids. In order to treat the effluent and to disperse the water, the soil treatment area must be an appropriate size. The size of the soil treatment area is primarily based on the size of the home and the type of soils of the soil treatment area. The size of the home suggests the potential levels of water usage and thus how much effluent the soil treatment area will need to process. The types of soils affect the ability of the drainfield to transmit the water, which is known as its conductivity. These two primary factors are used in designing the septic system.

   The biomat, a thin layer of fine solids, dead bacteria, and soil bacteria, naturally forms where the effluent enters the soil of the drainfield. The biomat sufficiently restricts the flow of the effluent to keep the soil beneath the drainfield unsaturated. The unsaturated soil contains oxygen, which allows aerobic bacteria to live and destroy pathogenic organisms. These air spaces also force nutrients such as phosphorus to come in direct contact with soil particles to which they become attached. A portion of the nitrogen contained in the effluent passes through into the groundwater. After passing through the unsaturated soil, the now treated effluent evaporates into the air or returns safely to the soil and groundwater system.

4. What Is Meant by a Septic System Failure?

    

   Failure of a septic system means that wastewater may enter the natural environment or come in contact with people, without complete treatment of all its harmful contents.

5. Why Do Septic Systems Fail?

    

   Septic system failure is usually a result of the lack of proper maintenance, overuse of water in the home, or improper system design or installation.  Septic system failure can sometimes also occur due to aging and fatigue of the system.

6. What Are Some Signs of a Septic System Failure?

    

   Signs that may suggest a failing septic system include:

   • Sewage/plumbing backup or sewage odors into the house

   • Slow draining sinks and toilets

   • Gurgling sounds in the plumbing

   • Puddles forming on the soil treatment area (drainfield) surface

   • Backflow into the septic tank from the drainfield during pumping

   • System alarms sounding (if present on the system)

   • Frozen pipes or frozen soil treatment area (drainfield)

   • Algae blooms and excessive plant growth in nearby ponds or lakes

   • High levels of nitrates or coliform bacteria (for example E. coli) in well water tests

 

 

Septic Tank Pumping and Maintenance

 

1. How often should my septic tank be inspected?

    

   It is recommended that your septic tank is inspected once a year.  This can be done by yourself or by having a service provider perform the inspection.  In addition to checking for leaks, cleaning filters, inspecting the baffles and other compontents, and determining the overall condition of your tank, the inspection should determine the amounts of solids (scum and sludge layers) in the tank and when the next pumping of the tank is needed. 

2. Why is it important that I have my septic tank pumped?

    

   Septic systems are not entirely maintenance free. For example, the undigested solids (sludge and scum layer) in the septic tank need to be periodically pumped out. If not removed, the sludge will gradually fill the tank, reducing its efficiency to breakdown the waste and can eventually carry over into the drainfield causing the field to fail. This leads to extremely costly repairs. As part of periodic preventative maintenance, the septic tank should be pumped out every two to five years with the frequency being dependant upon usage levels and tank size. Regular Septic System pumping of the Septic Tank will reduce accumulation of the sludge and scum layer in the Septic Tank. The scum layer should never reach 24 inches thick.

3. How often should I have my septic tank pumped?

    

   The frequency of pumping is dependent upon the size of the tank and the amount of use including the number of people using it.  The use of a garbage disposal may increase the frequency needed for a septic system to by pumped.  As a general guideline, your septic tank should be pumped every 2 to 5 years.  If the bottom of the scum layer is within 6 inches of the bottom of the outlet tee, or if the top of the sludge layer is within 12 inches of the bottom of the outlet tee, your tank needs to be pumped. The scum layer in the tank should never be allowed to reach 24 inches thick.  We have provided on our "Documents" page a table, as well as a worksheet, to help estimate the frequency your tank may need pumping.  Also, we can consult with you personally on your specific situation to help identify the best frequency for you and your system.

4. I heard I shouldn't flush toilet paper into my septic system. Is this true?

    

   No, this is not true.  While limiting the amount of solids into your system is a good practice, toilet papers are designed to readily break down in septic treatment systems.  It is recommended not to flush other papers such as paper towels, facial tissues (Kleenex), baby wipes, feminine napkins or disposable baby diapers since these do not break down as easily.

5. I have seen ads for septic additives that claim I don't need to have my spetic tank pumped if I use their product. Do these really work and are they a good idea?

    

   Some makers of septic tank additives claim that their products break down the sludge in septic tanks so the tanks never need to be pumped.  These claims are controversial and not widely accepted by independent experts in the Septic Tank Services field.  In addition to questions regarding the effectiveness of additives, some of them may actually be harmful to the system and inhibit a system's effectiveness.  Both the U. S. Environmental Protection Agency (EPA) and the Montana Department of Environmental Quality (DEQ) advise that good management practices and periodic pumping is a much better way to ensure that septic systems work properly and provide many years of service.  Bottom line, every septic system tank requires periodic pumping.