How does a Septic Tank work?
As the septic system is used, there is an accumulation of solids in the tank, which is sometimes referred to as sludge. The septic tank removes solids by holding wastewater in the tank for at least 24 hours, allowing the solids to settle and scum to rise to the top. This is accomplished by a series of baffles inside the tank. Up to 50 percent of the solids retained in the tank will decompose over time. Treated effluent water discharges from the tank to perforated drain pipes. From there, it drains to a constructed absorption or leach field. The effluent eventually percolates through the subsoil to groundwater.
Septic Tank Maintenance
As you use your septic system, sludge will accumulate in the tank. Properly designed tanks have enough space for up to three years of safe accumulation. Once the sludge has reached this level, the separation of solids and scum no longer takes place, and sewage may overflow into the absorption area. This can be prevented by periodically pumping the accumulated sludge.
How often should you pump?
This depends on the following:
Safe use of septic systems
Do not put substances such as motor oil, gasoline, paints, thinners, and pesticides in drains. These materials may pollute the groundwater and are toxic to the microorganisms that maintain an active septic system. Moderate use of household cleaners, disinfectants, detergents, or bleaches will do little harm to the system, but remember that where there is a high density of septic systems there may be a cumulative impact on groundwater from household cleaners. Fats, grease, coffee grounds, paper towels, sanitary napkins, disposable diapers, and other such items will clog your septic system.
Protect the absorption field
Keep automobiles and heavy equipment off the absorption field. Grass cover and shallow-rooted plants are beneficial over the absorption field, but the deep roots of trees and shrubs stress and may plug nearby drain tiles. Do not fertilize the soil above the drain field. Grass on the surface of an absorption field should be mowed regularly to promote evaporation and removal of water through the leaves. This helps prevent water from unnecessarily infiltrating the soil
above the absorption field.
Conserve water
Remember to consider the capacity of your septic system when installing new appliances or plumbing. Limit the water entering the tank. Use water-saving fixtures. Repair toilet float valves, leaks, and dripping faucets.
Avoid septic tank additives
Yeasts, bacteria, enzymes, and chemicals are sold with the claim of helping septic systems work better; however, there is no scientific evidence that additives are effective. In fact, some cleaners allow the solids in an overloaded tank to be re-suspended and clog the drainage lines. Additives are not an alternative to proper maintenance and do not eliminate the need for routine pumping of a septic tank. Commercial biological additives are not necessary for restarting decomposition after pumping because the sludge residue contains active microorganisms.
How to recognize problems
Learn how to recognize problems with septic systems. For example, unusually lush and green grass over your drain field may indicate trouble. Also, pay attention to slow-draining toilets or drains, sewage odors, or sewage backing up into the house or over the drain field.
Checklist for Good Septic Tank Maintenance