Across the Director's Desk

Septic systems serve an important function in rural homes and they need regular maintenance. Understanding how they work will help you avoid problems and costly repairs.
A conventional septic system has two primary parts: the tank and the soil absorption field (sometimes called a leach field) biologically treats the wastewater and soaks it into the soil absorption field from things that would cause it to fail, namely grease and solids.
As wastewater leaves the house through the sewer line, it enters the septic tank. Heavier solids settle to the bottom as sludge. Lighter grease and floating solids rise to the top as scum. Sludge and scum are trapped in the tank, allowing cleaner liquid to pass from the tank to the soil absorption field for treatment and disposal.
Bacteria may decompose some of the scum and sludge, but the rest needs to be periodically removed. This occasional maintenance is required for all septic tanks. There are no additives that eliminate this need. Failure to remove sludge or scum can cause these materials to pass into the soil absorption field where they can plug the system, causing failure and expensive repair.
Caring for a septic system
Be conservative in your water use. The more water you use, the more that must go through the absorption field.
Be careful what you put down the drain. Toxic materials can harm bacteria in the septic tank and pollute ground water. Fats, grease, coffee grounds, sanitary napkins, disposable diapers, and cat litter decompose slowly, if at all and will fill the septic tank quickly.
Protect the absorption field. Keep cars and heavy equipment off it. Tree and shrub roots may plug the drain lines.
Avoid septic tank additives. Yeasts, enzymes, bacteria, and chemicals are not necessary, and some are harmful.
Clean your septic tank every three to five years.
For more information, including ways to estimate and measure sludge and scum accumulation, ask the ISU Extension office for publication AEN-133, Maintaining the Home Septic System.