The Difference Between a Sewer System and Septic System
Whether building your dream home or buying an existing home, it is important to understand what type of system is required or in place for the drainage and treatment of wastewater. The two types of systems are sewer and septic. In many instances, the choice of what system you will need to use will be based on the planning and zoning municipality where your property is located. If the area has a sewer system, the home is more likely to be connected to that system. However, a septic system gives the freedom to live in a rural area not served by a sewer system, or where the connection to a sewer system is too expensive.
While sewer systems and septic systems serve the same general purpose, which is the drainage and treatment of wastewater, each system operates differently and on varying scales. So, what’s the difference between a sewer system and septic system?
Below is an overview of the two systems along with some pros and cons of each.
Sewer System Overview
The sewer system is the system more people are familiar and comfortable with. A sewer system is a shared, large-scale public utility system maintained by the local municipality’s public works department. Sewer systems connect an entire community using city-owned pipes and sewer lines that lead to a centralized treatment facility. The treatment facility treats the water in various stages to remove solids, organic materials, bacteria phosphorus, and nitrogen from the water and discharge it back into the local water supply.
The pros of a sewer system
No individual maintenance by the property owner because all maintenance is performed by the municipality
Sewer systems are designed to manage large volumes of wastewater and stormwater and are less susceptible to overflow during big rainstorms (although overflow can occur)
If there is a problem, the property owner calls the local municipality instead of having to fix it themselves
Flush or wash down the drain and forget it…the wastewater is gone
Due to their familiarity, sewer systems are often preferable by homebuyers
The cons of a sewer system
Municipalities charge a monthly fee to the property owners for use of the sewer system and periodically assess a larger fee for maintenance, repairs, and new installations
When building a new home, municipalities generally charge an “impact” fee to connect the new home to the sewer system, which can be very expensive
Ideally, a sewer system will take advantage of gravity as much as possible to get the wastewater to the central treatment facility, but the lay of the land often requires that energy be used to pump the wastewater throughout the system to get to the treatment facility
The centralized treatment facility uses chemicals for treating the wastewater before returning back into the environment or local water supply
Septic System Overview
Where an area is not served by a large scale, public sewer system or the cost of connection is too high, a septic system installed on an individual property is used for the local treatment of wastewater. In this system, a large steel or concrete tank is buried in the yard of the property owner. Most septic tanks can hold approximately 1,000 gallons. Wastewater from the home is sent to the septic tank where it enters one side and is filtered out through the other side and then enters a drain field. While in the tank, the wastewater forms three layers. The top layer is known as the scum layer and is formed by anything that floats to the top. Any heavy material will sink to the bottom and create the sludge layer. Between the scum and sludge layers is relatively clear water containing bacteria and fertilizing chemicals such as phosphorus and nitrogen. Through the breakdown of organic materials, the septic tank will produce gases, which is released through a vent pipe routed through the rooftop of the home.
Septic tanks require the proper maintenance by the homeowner to be effective and avoid any malfunctions. Depending on the type of tank and local laws, a septic tank generally needs to be pumped out every 2-5 years. With proper maintenance, a steel tank can last 15-20 years while a concrete tank can last upwards of 40 years.
The pros of a septic system
No monthly fee
Pumping performed every 2-5 years is generally the only ongoing cost and typically costs between $200-400.
Often considered a greener option due to being powered entirely by gravity and no chemicals are used to treat the wastewater
Allows homes to be built in rural areas where sewer systems are not available or where the connection to a sewer system is cost-prohibitive
The cons of a septic system
Maintenance is the responsibility of the property owner
The cost of installing a new septic system may be a larger upfront cost versus the fee to connect to a sewer system
If not properly designed and maintained, a septic system can be more susceptible to malfunction or overflows during periods of heavy rains
If not properly designed and maintained, the water may not be properly treated and outflow can contaminate the surrounding area
You will need to allow space on your property for the underground septic to be located
Conclusion
Both a sewer system and septic system can adequately treat wastewater. While septic systems have not always been favored by homebuyers, properly maintained septic systems can be a cost-effective and a greener option than sewer systems.
Septic systems also allow the freedom to build a home wherever there is proper soil. Although it is important to understand what system the home uses or will need to use, the type of wastewater system should not necessarily be a determining factor in deciding where to build or purchase a home.
