Frequently prospective buyers of a single-family home have many questions regarding the septic system serving the dwelling:
- What does the existing septic system consist of?
- Is it working properly?
- How long will it last?
In order to help buyers obtain Information that addresses these concerns.
We have put together this Fact Sheet to guide them in making informed decisions regarding the potential problems and costs associated with a property’s septic system.
Overview of Septic Systems
The purpose of a home’s subsurface sewage disposal system (septic system) is to dispose of the water generated by the occupants in such a manner that the soils on the property can disperse it without causing an adverse effect on groundwater and in turn on public health and the environment.
To accomplish this a septic system consists of the following elements:
- A sewer line that connects the home’s plumbing to the septic tank;
- A septic tank that allows for the settling of soils and provides the initial treatment of the septage. A properly functioning septic tank will reduce pollutant levels and produce an effluent of fairly uniform quality. This is accomplished by providing inlet and outlet baffles to reduce the velocity of liquid moving through the tank and to prevent solids from leaving the tank. Tanks installed since January 1991 now consist of two compartments in order to do a more effective job of attaining the above objective;
- A distribution system that directs the flow of effluent from the septic tank to the leaching system in such a manner to ensure full utilization of the system. Most systems are “gravity” systems, meaning the flow runs through piping and distribution boxes without the assistance of any mechanical device, such as a pump or siphon;
- A leaching system, which disperses the sewage effluent into the surrounding natural soils. There are many types of leaching systems. The specific type utilized on a particular property is usually dependent on the soil conditions which exist on the site. Most residential installations utilize stone-filled leaching trenches, but galleries, pits and beds have historically been used.
For a leaching system to function properly it must:
- Provide enough application area. The application area is the amount of surface area of soil within the leaching system where sewage effluent is applied (referred to as “wetted” area). The amount of application area needed for a given house depends on the characteristics of the soils on the property and the daily flows (in gallons) generated from the house.
- Be surrounded by natural soil conditions which will be able to dissipate and disperse the discharge without becoming oversaturated.
- Provide enough capacity to store effluent during periods of unusually heavy use or when rainfall or subsurface flooding reduces the ability of the system to disperse the liquid. Note: Curtain drains or groundwater interceptor drains are sometimes installed an upgrade of the leaching system to minimize high groundwater conditions.
It is important to realize that, once a system has been installed, only one of the above factors can be controlled by the homeowner.
The homeowner can control how much water is actually being discharged to the system.
Since each system has a set maximum capacity, it behoves the homeowner not to exceed that amount.
If a system starts to experience difficulties, what are some of the common symptoms?