What is the primary difference between a sewer system and a septic system?

The primary distinction between a sewer system and a septic system lies in how they handle wastewater. A sewer system is designed to transport wastewater from homes and businesses to a centralized treatment facility, where it is processed and treated before being discharged, typically into a water body or back into the local water supply after being treated. This centralized approach facilitates the treatment of wastewater from multiple sources, relying on infrastructure managed by local municipalities or utilities.

On the other hand, a septic system functions independently for individual properties. It consists of a septic tank and a leach field, where wastewater is treated on-site. In a septic system, solid waste settles at the bottom of the tank, while bacteria within the tank help break down the waste. The liquid effluent then flows into the leach field, where it further percolates into the soil. Unlike a sewer system, septic systems are not linked to a central treatment facility, making them suitable for rural areas or places where connecting to a sewer system is not practical.

Thus, the concept of a sewer system discharging treated wastewater back into a local supply is a defining characteristic, highlighting the communal nature of sewer systems as opposed to the individual, on-site treatment provided by septic systems.