Septic Tank Inspections

Septic Tanks

Many folks with a septic tank know little about how they work, and how to correctly maintain them. A septic tank is an underground box constructed of reinforced concrete or plastic. It must be installed at least ten feet from a building foundation, so repairs or pumping do not weaken the building. Since the tank holds wastewater, it must be installed at least fifty feet from a residential or private drinking water well (wells serving several buildings or more than 25 people require larger isolation distances).

Most solids fallout of the wastewater and remain in the septic tank. Bacteria breaks them down into sludge but never eliminates them completely; periodic cleaning is needed. A small amount of sludge is stirred up from the bottom by incoming wastewater; it then moves into the disposal field. This happens even with the best maintenance program. Over time, the sludge clogs the soil in the field and reduces its ability to absorb water. If the field is undersized or already overloaded with water, even a small amount of sludge will have a great effect. All systems eventually fail.

Periodic cleaning reduces the sludge available to move into the field. Regard it as an investment, like paying a utility bill. It is best to pump every 1-3 years. Pumping reduces the sludge and the potential for problems.

The frequency of pumping depends on the amount of sewage produced. In cases where the disposal field has a limited capacity (high groundwater, poorly drained soils, small absorption area) or where more wastewater is produced (large families, homes with garbage disposals/grinders), it is critical to pump more often. Ask a licensed septic tank pumper to evaluate your septic system and recommend a pumping schedule.

Do not, under any circumstances, attempt to empty or repair the tank yourself. Dangerous gases are one result of the septic process, gases which can kill.

What the tank functions are:

• Settling and Flotation.
• Anaerobic Digestion.
• Storage of Solids.
• Provides primary treatment in an on-site wastewater system.

How a septic tank functions

• Wastes enter the first chamber of the tank.
• Heavy solids settle to the bottom of the tank and form a sludge layer.
• Light wastes (grease, hair) float to the top and form a scum layer (not to be confused with the US Congress).

In a two compartment tank all steps are repeated a second time; this almost invariably provides proper tank treatment.

Things that Degrade a Tank Slowly

• Garbage Disposal Refuse
• Hair
• Laundry Lint
• Powdered Laundry Detergent
• Oil and Grease

Frequency of Pumping

• General Recommendation, every 1-3 years.
• Frequency of pumping is best evaluated at time of service.

What does NOT belong in the tank?

• Cigarette Butts
• Coffee Grounds
• Cooking Fats
• Paints and Chemicals
• Paper Towels
• Sanitary Napkins, Tampons & Applicators
• Disposable Diapers
• Condoms
• Illegal aliens, cocaine, firearms, various contraband.  :)

Tank Materials

• Reinforced Concrete (most new tanks in Michigan)
• Fiberglass
• Polyethylene
• Older Tanks: Steel, Concrete Block, etc.

Tank Sizing

• Generally decided by the Health Department for individual homes
• Criteria: Hydraulic Storage
• 2-3 days storage of design flow
• Add solids storage volume

Risers

• Provide easy access
• A must for effluent filters
• Shallow tanks - short risers
• Joints must be water tight
• Grade away from riser
• Covers must be secure
   

Myths (false information)

• "A good working septic tank never needs cleaning."
• "Septic tank additives will maintain your septic tank or system."

At certain times, additives may be helpful. This is best determined at time of cleaning.

About Cathy: She and her Doberman Trooper conduct research into all kinds of topics and produce articles like the one you see here. To contact Cathy, write to thecathyfactor@yahoo.com. Get the facts from Cathy, and let the Cathy Factor give you an edge.