Gravel vs PVC Vault Drainfields
Learn about the important differences between specifying drainrock or PVC vault technologies in septic system design. Let us compare a septic system to a car. The septic drainfield is like the car’s exhaust system, including its catalytic converter, muffler, and tailpipe. The drainfield is where the wastewater from the house becomes safe before it empties into the natural landscape.
In the past, almost ALL drainfields were built up with drainrock (a form of washed, uniform gravel.) The drainfield would spread the water from the system underground over a specially prepared area, usually in the back yard. Over the last twenty years or so, the function of the drainfield has not changed. However, plastic half-pipes, or vaults have replaced drainrock in the drainfields of most of the new systems built today.
This module contains complete construction drawings with full specs and calculations for both a typical pressure septic system, and a modern gravity system. Drainrock drainfields will always have a place in septic design in a number of specific situations, so when designing systems, you will need to understand both. We advise where and when to use each one. This module contains over 20 drawings, many construction images, instructions, and notes.