Septic System Additives

by Russell Derickson, Extension water and natural resources specialist, South Dakota State University Ag Engineering Department

If your on-site wastewater treatment system develops problems or fails, don't be so anxious to find a solution that you'll try any product that comes along. Many people with septic systems are confused by magazine and TV advertisements, as well as telephone solicitations, for onsite system additives. On-site system additives are not needed and are not recommended by the South Dakota Cooperative Extension Service. To understand why you do not need on-site system additives, evaluate the product by answering the following questions:

On-site system additives can be classified into two general categories: they are either safe, or they are effective. The effective additives are not safe, and the safe additives are not effective. Unsafe additives travel to the treatment field and cause groundwater contamination.

Some additive companies claim that on-site system problems are caused by household cleaners and that their product will re-supply needed bacteria populations. Their products contain yeasts or bacteria to stimulate microorganism action in the septic tank.

Normal or average use of household cleaning chemicals will not cause problems with on-site systems. Every time the toilet is flushed or the sink is drained, bacteria are naturally re-supplied to the septic tank. If bacterial activity in the septic tank is low, it is because the homeowner has added a detrimental product to the wastewater stream.

Other companies sell cleaners or degreasers as additives that agitate septic tanks and cause scum and sludge to enter soil treatment fields.

They claim that their products will eliminate the need for septic tank pumping by re-suspending solids and flushing them into the treatment fields. Once in the treatment field, the solids plug soil pores. Plugged soil pores cause a reduction in the treatment field's capacity and efficiency.

Septic tanks are specifically designed to trap and prevent solids and floating materials from entering soil treatment fields.

The best advice for homeowners.:

Pumping septic tanks is the best preventative maintenance measure for on-site systems.


Return to the Septic Tank area of the SwopNet Engineering Databank. You will find lots more information about on-site wastewater disposal there.