How does the size of a gray water system compare to that of a residential septic system?

Gray water systems are designed to handle water that is relatively clean, coming from sources such as sinks, showers, and laundry, as opposed to black water, which contains human waste and pathogens. Because gray water does not require the same level of treatment as black water, these systems can be designed to be smaller in size compared to traditional residential septic systems, which need to accommodate more complex treatment and larger volumes of waste.

This difference in requirements is mainly due to the reduced risk of contamination and lower volume of solids involved with gray water. As such, a gray water system prioritizes efficiency and resource recovery while being more compact and easier to install in many situations. The design considerations for a gray water system focus on its ability to recycle water for irrigation or similar uses, supporting sustainability efforts within residential environments.