InspectAPedia ®

Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice
InspectAPedia
Home
| Air
Conditioning
| Electrical | Indoor
Environment
| Exteriors | Heating | Home
Inspection
| Insulate
Ventilate
| Interiors | Mold
Inspect/Test
| Plumbing
Water
Septic
| Roofing | Structure | Contact Us
Directory of Professionals to Inspect or Test a Building


SEPTIC SYSTEMS HOME
SEPTIC INFO ARTICLES
HOME BUYERS GUIDE to SEPTIC SYSTEMS
SEPTIC INSPECT & TEST
SEPTIC SYSTEMS ONLINE BOOK
INTRODUCTION
SEPTIC SYSTEM SAFETY WARNINGS
SEPTIC SYSTEM DESIGN BASICS
  SEPTIC SOIL & PERC TESTS
  SEPTIC TANK SIZE
  SEPTIC DRAINFIELD SIZE
  SEPTIC DRAINFIELD SHAPE
  SEPTIC CLEARANCES
  SEPTIC TANK PUMPING FREQUENCY
  SEPTIC TANK PUMPING PROCEDURE
  SEPTIC PUMPING REPAIR
  SEPTIC TREATMENTS
SEPTIC DESIGN ALTERNATIVES
  AEROBIC SEPTIC SYSTEMS
  ALTERNATING BED SEPTIC SYSTEMS
  CESSPOOLS
  DRYWELLS
  SEPTIC EFFLUENT DISINFECTION SYSTEMS
  EVAPORATION-TRANSPIRATION SEPTIC SYSTEMS
  FIXED-FILM PROCESS SEPTIC SYSTEMS
  GRAVELLESS SEPTIC SYSTEMS
  LAGOON SEPTIC SYSTEMS
  PRESSURE DOSING SEPTIC SYSTEMS
  MEDIA FILTER SEPTIC SYSTEMS
  SEPTIC & GREYWATER FILTERS
  SEQUENCING BATCH SEPTIC SYSTEMS
  MOUND SEPTIC SYSTEMS
  RAISED BED SEPTIC SYSTEMS
  SAND BED SEPTIC SYSTEMS
  SEWAGE TREATMENT SYSTEMS
  TOILET ALTERNATIVES
  SEPTIC SYSTEM PUMPS
SEPTIC DRAINFIELD INSPECTION & TEST
  SEPTIC D-BOX INSPECTION
  SEPTIC DYE TESTS
  SEPTIC FAILURE SPOTS
  SEPTIC FIELD FAILURE CAUSES
  DISPOSAL CLOGGING FAILURES
  DISPOSAL vs TREATMENT
  SEPTIC DRAINFIELD LIFE
  SEPTIC FAILURE CRITERIA
  SOIL CONDITIONS
  PLANTS OVER SEPTICS
  SEPTIC FAILURE LAWSUIT
  SEPTIC INSPECTION WORK SHEETS
SEPTIC SYSTEM FAILURE CAUSES
SEPTIC TANK INSPECTION PROCEDURE
SEPTIC SYSTEM DEFINITIONS
SEPTIC FAILURE LAWSUIT
SEPTIC REFERENCES
SEPTIC CONSULTANTS
SEPTIC AUTHORITIES
SEPTIC SYSTEM BOOKS REFS CODES
SEPTIC SYSTEM DESIGN MANUAL - Online

More Information

InspectAPedia.comInspectAPedia ® Home & Site Map
InspectAPedia Blog - News Updates
Air Conditioning & Heat Pumps
Bookstore
Electrical
Environment
Exteriors
Heating
Home Inspection
Insulate Ventilate
Interiors
Mold Inspect/Test
Roofing
Plumbing Water Septic
Structure
Accuracy & Privacy Policies
Contact Us



Photograph of  a modern concrete distribution box - in this case, stacked up at the manufacturing facility in Kingston, NY

Inspecting &Testing the Septic System Distribution Box
InspectAPedia®  -    

  • How to find the septic drainfield D-box - septic distribution box
  • How to inspect the septic system distribution box for clues of septic drainfield condition
  • Simple repairs at the D-Box can improve septic drainfield performance and may eliminate septic odors
Our site offers impartial, unbiased advice without conflicts of interest. We will block advertisements which we discover or readers inform us are associated with bad business practices, false-advertising, or junk science. Our contact info is at InspectAPedia.com/appointment.htm.

Here we discuss procedures for locating and inspecting the septic drainfield distribution box, or the "D-box". This series of articles discusses Inspection and Reporting the Condition of Private Residential Waste Disposal Systems - or - Where Does it Go When I Flush? and ... Will We Meet Again?

© Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use the links at page left to navigate this document or to go to Other Website Topics. Green links at left show where you are in our document & website.

INSPECTING THE D-BOX - Inspecting the Septic System Distribution Box

photo of a septic distribution box used to connect the septic tank effluent outlet line to a network of
drainfield pipesThe distribution box (more than one may be in use) connects a single effluent line from the septic tank to a network of absorption system components such as drainfield leach lines or to a network of seepage pits or galleys.

The photo (left) shows the adjustable weir outlets that permit balancing flow among drainfield lines. (Source EPA who used photo from Ayres Associates.) More sketches of D-box layouts and configurations are shown in this EPA drawing.

Regulating effluent distribution: In good system design the outlet openings from the distribution box to each drainfield line can be adjusted to regulate the flow among the various absorption lines.

Elegantly simple, a plug with an eccentric hole is inserted into the end of each leach line fed from the D-box. By turning the plug in the end of the leach line pipe one can place the eccentric hole higher or lower with respect to the bottom of the distribution box, thus compensating for a slightly tipped box, differences in leach line length, or differences in leach line condition.

Uneven effluent distribution: If a distribution box becomes tipped (or clogged) effluent may be routed to only a portion of the absorption system, thus overloading it and leading to a "breakout" of effluent at the surface or to clogging and system backup.

An examination of the septic system distribution box interior may show flood lines in the box if the drain field has been clogged or saturated in the past even if at the time of inspection the box is not flooded.

If the septic drainfields have been flooded you should be pessimistic about the remaining life of the absorption system.

If the septic drainfield distribution box is tipped and/or septic system effluent arriving from the septic tank has not been uniformly distributed among the drainfield lines (assuming they are of equal length and in equally good soils), only a simple adjustment of the outflow may be needed.

Round plugs with eccentric openings may be present or can be inserted in the D-box outlet openings to regulate flow among the individual absorption lines. (C)Trap Daniel Friedman Copyright Protected text. Also see ALTERNATING BED SEPTIC SYSTEMS.

Tipped or flooded distribution boxes, resulting in uneven loading of soil absorption system lines. This condition can flood one or two lines leading to early field failure.

Share this Article      

...

Technical Reviewers & References

  • Daniel Friedman - principal author/editor of the InspectAPedia® Website
  • InspectAPedia Bookstore lists recommended books, organized by topic & available for purchase. Most of our articles also include a list of recommended books for the specific article topic as well as other references, and information sources.
  • Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
  • Additional technical contributors & reference sources for this article are listed below.

Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.

SEPTIC DRAINFIELD INSPECTION & TEST
  SEPTIC D-BOX INSPECTION
  SEPTIC DYE TESTS
  SEPTIC FAILURE SPOTS
  SEPTIC FIELD FAILURE CAUSES
  DISPOSAL CLOGGING FAILURES
  DISPOSAL vs TREATMENT
  SEPTIC DRAINFIELD LIFE
  SEPTIC FAILURE CRITERIA
  SOIL CONDITIONS
  PLANTS OVER SEPTICS
  SEPTIC FAILURE LAWSUIT
  SEPTIC INSPECTION WORK SHEETS
SEPTIC SYSTEM FAILURE CAUSES
SEPTIC TANK INSPECTION PROCEDURE
SEPTIC SYSTEM DEFINITIONS

Readers of this page should also see System Design Regulations 75-A.7 Distribution lines, distribution boxes, gravity flow, pressure distribution, dosing, siphons design specifications for septic systems.

More Information on Building Diagnostic Inspections and Repairs

InspectAPedia.comInspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
GO TO the MOLD and INDOOR ENVIRONMENT INFORMATION CENTER for in-depth advice on avoiding testing for or cleaning up mold and other indoor environmental hazards, odors, gases, contaminants
The Mold Information Center:
What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
GO TO MOLD TEST KITS: This expert-recommended mold test kit is cheap and yet top performing *IF* you use a competent analysis laboratory!
Use this simple, economical mold test kit
by following our instructions on how to collect and mail mold samples to our lab
GO TO IAQ/MOLD-TEST LAB SERVICES: Mold, Pollen, indoor air quality, field and laboratory services by an expert.Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.
GO TO our PRE PURCHASE BUILDING INSPECTION SERVICES: Authoritative information for home buyers and home owners is included with your inspection.
Building Inspection, Problem Diagnosis
, Forensic Investigation & Testing, Repair Consulting

CONTACT Daniel Friedman - Dan is a senior ASHI home inspector, nationally recognized expert on building inspection, building failures, and sick building investigation
Contact Daniel Friedman for website content suggestions or for fee-paid consulting

10/23/2009 - 11/14/1995 - InspectAPedia.com/septic/DBox.htm - © 2009 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark