Be sure to dig your drainfield excavation where it has been approved. We are working to provide an illustration of a standard drainfield on-line. Yours may differ. See your permit. A tee should be installed on the outlet of each septic tank that does not have a built-in baffle.
B equals the length of the tee below the invert of the outlet of the pipe leaving the septic tanks.
For a septic tank 800 gallons or greater, B equals 24 inches. For a septic tank less than 800 gallons, B equals 18 inches. The first tank should be the larger capacity septic tank. See permit for required tank capacities. Locate your septic tanks away from heavy vehicle traffic.