As I travel across the country and discuss gravity distribution, one of the biggest variations I see is how the effluent is delivered to the trenches. Flow to gravity distribution systems is directly related to use at the source: effluent from the septic tank flows to the soil treatment area whenever sewage enters the septic tank.Gravity distribution of septic tank effluent has been the most common design over the history of onsite treatment in the U.S. Less expensive to install and maintain than systems in which effluent is pumped, gravity distribution systems take advantage of natural elevation differences. Effluent flows
