Introduction

Septic Systems

General

Maintenance of septic systems is often forgotten because they are underground and "out of sight and out of mind". Our Lake Management Plan lists nutrient influx into our lake as the major water quality concern. The plan goes on to identify inadequate or malfunctioning septic systems around our lake as the primary source of this nutrient influx.Properly designed, constructed and maintained septic systems pose little threat to the environment and human health. However, improperly functioning systems pose a contamination risk to groundwater and our lake. A marginal septic system is more likely to contribute poorly treated sewage to our lake. Disease-causing organisms found in this wastewater can cause dysentery, cholera, typhoid and hepatitis A. Improperly treated nitrates can contaminate drinking water in nearby wells and lead to illness in humans, including blue baby syndrome, which affects an infant’s ability to carry oxygen in their blood. Other nutrients, primarily phosphorous, can promote algae and weed growth in our lake. Assuming you have a properly designed and functioning septic system, the following information is an overview of system function, use and recommended maintenance.

How a Septic System Works

Waste material from the house enters the septic tank and heavier solids settle to the bottom of the tank and form a sludge layer. Lighter household wastes such as oil and grease rise to the top of the tank and form a scum layer. Between these two layers is the liquid wastewater sometimes called effluent. When combined waste enters the tank, bacteria breaks down the solid materials. This break down dramatically reduces solids, but still leaves a residue behind in the tank. The center liquid layer flows slowly from the tank through a distribution box and out into “fingers” of a drain or leach field where the treated liquid wastewater is filtered through gravel or crushed rock back into the soil. The soil under the drain field then acts as the final filter for the wastewater before it goes back into the groundwater.