Septic system D-box or drop box layout in the septic system - US EPA 1980 Septic System D-Box Piping
Install Piping to & from the System Drop Box

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Septic system drop box piping: what type & size of pipe is used from septic tank to D-box and from D-box into the septic drainfield or soak-bed trenches?

Septic system D box installation, specifications, inspection, diagnosis, and repair: in this article series about septic system drop boxes we describe the best procedures for locating and inspecting, repairing or replacing the septic drainfield distribution box, or the "D-box" or "Splitter box".

If the D-box is leaking, smells, or is tipped, clogged, or otherwise not working this article describes how to diagnose & fix the trouble.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

Septic D-Box Piping

Septic system drop box or D-box being installed, Tucson AZ (C) Daniel FriedmanQuestion: are the pipes from the D-box solid or perforated?

are the pipes leading from the D-Box have a drywell system) solid or perforated, , one side of the yard is very wet, the other side seems bone dry, could one the pipes either clogged or the other broken, not sure which one to dig up 1st - Joe M

Reply: It depends on septic drainfield layout

Our photo (left) shows a septic system drop box or D-box being installed in a new septic soakaway bed in Tucson, Arizona in the U.S.

Joe the use of solid vs. perforated pipes downstream from the D-box would depend on the septic field layout, but typically from the D-box there will be a solid effluent-carrying pipe serving as a manifold that then feeds individual perforated lines in drainfield trenches.

In theory in my OPINION there is nothing preventing the beginning of gravel-trenches quite close to the d-box, in which case wherever the pipe is running in a gravel trench intended to absorb effluent, the pipe would be perforated.

But I would NOT run perforated effluent piping through mere soil backfill (i.e. not a gravel-filled trench) as you'd be inviting soil infiltration and clogging of the line.


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