Once thought of as temporary sewage treatment measures, we now recognize these systems are here to stay. Individual, on-site sewage treatment systems (septic) are typically regulated solely by requiring a permit for installation. Septic systems are responsible for dispose of a variety of household sewage, or wastewater, generated from toilet use, bathing, laundry, and kitchen and cleaning activities.
As these systems are underground and seldom require daily care, many homeowners rarely think about routine operations and maintenance. However, if a septic system is not properly designed, located, constructed, and maintained, groundwater may become contaminated or the system could back up completely.
A conventional septic system has three basic working parts, which include a septic tank, a drain field, and surrounding soil. Septic tanks are typically constructed of concrete, fiberglass, or plastic and must be approved by the state. Minimum size tanks have been established for residences based on the number of bedrooms in the dwelling. A typical size tank for a three or four bedroom home is 1000 gallons. The health departments are responsible for issuing permits for septic systems and specify the minimum size tank.
Upon entry into the septic tank, the flow rate of the wastewater which was previously routed from the house by way of drain lines slows dramatically. This allows for heavy particles to settle or fall from suspension to the bottom of the tank. The remaining flowable wastewater then enters the septic drain lines as shown to the right.
Septic drain lines are used to remove contaminants and impurities from the liquid that emerges from the septic tank. This is accomplished by using perforated lines that basically leak out the liquid into the surrounding soil. The length and number of lines required is determined by the size of the system and the soils ability to absorb the moisture.
The soil around and below the drain field provides the final treatment and disposal of the septic tank effluent (wastewater discharge). After the effluent ahs passed into the soil, most of it disperses outward and downward, eventually entering the groundwater. The soils ability to “clean up” the effluent discharge is critical in this process. A system that is not functioning or designed properly will release nutrient-rich and bacteria-laden wastewater into the groundwater. These contaminated water pose a significant threat to public health when contacted. This is especially important to nearby wells for drinking water.
As mentioned earlier, to have a septic system installed on your property, you must obtain a permit from your local health department. Then a site evaluation is performed to determine the properties of the soil, mainly those affecting the ability of the soil to absorb moisture. If the soil does not have the appropriate moisture absorbing properties, the septic system will not be approved. Once approved, only have the septic systems installed by a licensed professional and inspected by your local health district.
In order to understand and maintain your septic system, you must first know where it is located. The location of the septic tank and drain lines can be determined from plot plans, septic system inspection records, landscape drawings, or from observations of the house plumbing and effects of the drain lines on the surrounding lawn. The septic tank is typically in the ground approximately 10 to 15 feet from the home.
Properly designed septic systems should have enough capacity fro three to eight years of use before needing servicing, which is directly related to the amount of discharge through the system. Between these servicing periods it is important to inspect your system annually and be aware of any changes in the systems performance. Sludge build up and scum accumulation can hinder the performance of your system. Solids may bypass the tank completely and enter the drain lines. This accumulation in the drain lines can cause a septic system back-up and in some cases discharge sewage backward into the house. For these reason, we recommend that your system be pumped every three to five years (or earlier if required by inspection). An accumulation of sludge exceeding 35% of the total water depth in the septic tank could cause solids to enter the drain fields and clog the system.
Although proper use, inspections, and maintenance should prevent most septic tank problems, it is still important to be aware of any changes in your septic system and its performance and to act immediately if you suspect failure. There are many signs of failure, but there are several of the most common listed below.