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.
This series of septic system installation, maintenance & repair articles discusses the Inspection and Reporting the Condition of Private Residential Waste Disposal Systems - or - Where Does it Go When I Flush? and ... Will We Meet Again?
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Definition of a Septic D-Box: a septic distribution box is a container used to receive septic system effluent from a septic tank and to re-distribute the effluent into a network of attached drain-field or soakaway bed absorption trenches & pipes.
The D-box works by gravity, flowing effluent into the drainfield (or leachfield) piping network.
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How far away from the septic tank is the dbox? - Kristin Clary
How far from the main tank is the D box located on average? - Fishass
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Kristin & Fishass: there is not a fixed distance from the septic tank to the distribution box; rather, its location depends on the space for and layout of the septic drainfield. But you can often get a fair idea where the D-box is likely to be by any of several means:
- running a snake or probe from the septic tank outlet until it stops will give the distance to the D-box (probably)
- look for a depression in the ground a couple of feet in diameter and between the septic tank and the drainfield.
- Look at the site layout for where the D-box could possibly be located. For example, if the drainfield site is level and rectangular, the D-box would typically be at or near the edge of the drainfield closest to the septic tank.
See SEPTIC DRAWINGS for some sketches that give an idea where the distribution box is typically found
The following building code example specification for septic system distribution boxes is excerpted from SEPTIC DISTRIBUTION LINES, BOXES, TYPES, NYS-A.7 Effective Date: 12/01/90 Title: Appendix 75-A.7 - Distribution devices
(i) For accessibility, it is necessary that the distribution box be located and have a removable cover not more than 12 inches below grade. Where, due to site conditions, a distribution box must be greater than 12 inches below the surface, an extension collar shall be installed to within 12 inches of the surface.
(ii) All outlets from the distribution box shall be at the same level to insure the even distribution of flow.
(iii) To minimize frost action and reduce the possibility of movement once installed, distribution boxes must be set on a bed of sand or pea gravel at least 12 inches thick.
(iv) The drop between inlet and outlet inverts shall be at least two inches. A baffle is required at the inlet side of the box when the slope from the septic tank to the box exceeds 1/2 inch per foot or when siphon dosing is used.
(v) There shall be a minimum two inch clearance between the inverts of the outlets and the bottom of the box to prevent short-circuiting and reduce solids carry-over.
(vi) Distribution boxes may be constructed in place or purchased prefabricated. When concrete is used to construct boxes, it shall have a minimum compressive strength of 2,500 psi at 28 day set.
(vii) Prefabricated boxes may be constructed of concrete, fiberglass, or plastic. The boxes shall be installed in conformance with the manufacturer's instructions in addition to the requirements above.
Continue reading at SEPTIC D-BOX INSPECTION
The 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.
Details are now at SEPTIC D-BOX INSPECTION
Question: are the pipes from the D-box solid or perforated?
Reply: It depends on septic drainfield layout.
Details are now at SEPTIC D-BOX PIPING
Reader question: I am being told that my D box is bad. When no levelers are in place all effluent runs into only one port.
Reply: Details about thorough inspection and diagnosis of Drop box problems are now at SEPTIC D-BOX TROUBLESHOOTING
Reader Question: water is leaking out of my distribution box. Should the lid be sealed?
Reply: Details about flooding, leaks and odors at the drop box are now at SEPTIC D-BOX FLOODING
Question: How to repair a bad D-box lid or cover
My D box lid has failed and the sides are starting to crumble.
Reply: Details about septic drop box covers have been moved to SEPTIC D-BOX COVERS
Reader Question: My d box is damaged, can I just eliminate it and plumb directly to the leach field lines?
Reply: yes but just in emergency - it's better to replace and set the D-box properly.
Details are now at SEPTIC D-BOX TEMPORARY REPAIR
Reader Question: What's the difference between a septic system D-box and a Splitter?
Reply: Basically there is no difference in function between a D-box and a Splitter box.
For details about drop box splitters and drainfield resting and recovery or Drainfield R&R approaches see SEPTIC D-BOX SPLITTERS
Continue reading at SEPTIC D-BOX INSPECTION or select a topic from the More Reading links or topic ARTICLE INDEX shown below.
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INDEX to RELATED ARTICLES: ARTICLE INDEX to SEPTIC DRAINFIELDS & D-BOXES
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Technical Reviewers & References
- New York State Department of Health, "Appendix 75-A Wastewater Treatment Standards - Individual Household Systems", [PDF] New York State Department of Health, 3 February 2010, retrieved 3/1/2010, original source: https://www.health.ny.gov/regulations/nycrr/title_10/part_75/appendix_75-a.htm
-  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.
-  Thanks to reader Nicholas Day for discussing D-box troubles and repairs, September 2010
-  Zoeller Pump Company, 3649 Cane Run Rd., Louisville, KY 40211, Phone: 1-800-928-7867, 502-778-2731 Fax: 502-774-3624. Technical support and/or quote related emails: email@example.com. Zoeller produces just about every kind of septic, sewage, effluent, grinder, and sump pump. Homeowners who need a sewage pump are asked to contact their local representative or retail sales outlet. Zoeller classes their pumps into these categories:
- Grinder pumps, such as Zoeller's 810/815 Turnkey Grinder Systems, 800-series Grinder Pumps, Cold-Climate grinder pumps, Simplex prepackaged grinder pump systems, and Simplex and Duplex (two pumps) grinder systems including four outdoor use.
- Utility, pedestal, & gas engine pumps. These are portable gas-engine powered pumps used typically in construction, service, or emergencies
- Sewage & Dewatering pumps, such as certain Aqua-Mate Models and Waste-Mate models, and Sewage-Waste 600-series pumps
- Splitter for septic effluent distribution. Web search 5/1/12, original source
https://app.qleapahead.com/rtp/LibraryGet.aspx?asset=85356,63 [copy on file as septic/D-boxes/Zoeller_D-BOx_Splittert.pdf ] Website: www.zoeller.com
- Sump, Effluent, Dewatering pumps, such as Water Ridd'r , Mighty-Mate, Aqua-Mate, Flow-Mate, and High Head Flow-Mate pumps - of certain models - be sure to read the manufacturer's intended use for a pump model before purchasing it
-  "Drainfield Rehabilitation", Pipeline, Winter 2005, Vol. 16, No. 1, NESC, National Environmental Services Center, 800-624-8301 [copy on file as [/septic/D-boxes/NESC_2005-16_1.pdf
-  Advanced Onsite Wastewater Systems Technologies, Anish R. Jantrania, Mark A. Gross. Anish Jantrania, Ph.D., P.E., M.B.A., is a Consulting Engineer, in Mechanicsville VA, 804-550-0389 (2006). Outstanding technical reference especially on alternative septic system design alternatives. Written for designers and engineers, this book is not at all easy going for homeowners but is a text I recommend for professionals--DF.
-  Builder's Guide to Wells and Septic Systems, Woodson, R. Dodge: $ 24.95; MCGRAW HILL B; TP; Quoting from Amazon's description: For the homebuilder, one mistake in estimating or installing wells and septic systems can cost thousands of dollars. This comprehensive guide filled with case studies can prevent that. Master plumber R. Dodge Woodson packs this reader-friendly guide with guidance and information, including details on new techniques and materials that can economize and expedite jobs and advice on how to avoid mistakes in both estimating and construction. Chapters cover virtually every aspect of wells and septic systems, including on-site evaluations; site limitations; bidding; soil studies, septic designs, and code-related issues; drilled and dug wells, gravel and pipe, chamber-type, and gravity septic systems; pump stations; common problems with well installation; and remedies for poor septic situations. Woodson also discusses ways to increase profits by avoiding cost overruns.
-  Country Plumbing: Living with a Septic System, Hartigan, Gerry: $ 9.95; ALAN C HOOD & TP; Quoting an Amazon reviewer's comment, with which we agree--DF:This book is informative as far as it goes and might be most useful for someone with an older system. But it was written in the early 1980s. A lot has changed since then. In particular, the book doesn't cover any of the newer systems that are used more and more nowadays in some parts of the country -- sand mounds, aeration systems, lagoons, etc.
-  Onsite Wastewater Disposal, R. J. Perkins; Quoting from Amazon: This practical book, co-published with the National Environmental Health Association, describes the step-by-step procedures needed to avoid common pitfalls in septic system technology. Valuable in matching the septic system to the site-specific conditions, this useful book will help you install a reliable system in both suitable and difficult environments. Septic tank installers, planners, state and local regulators, civil and sanitary engineers, consulting engineers, architects, homeowners, academics, and land developers will find this publication valuable.
-  Onsite Wastewater Treatment Systems, Bennette D. Burks, Mary Margaret Minnis, Hogarth House 1994 - one of the best septic system books around, suffering a bit from small fonts and a weak index. (DF volunteers to serve as indexer if Burks/Minnis re-publish this very useful volume.)While it contains some material more technical than needed by homeowners, Burks/Minnis book on onsite wastewater treatment systems a very useful reference for both property owners and septic system designers. We refer to it often. While Minnis says the best place to buy this book is at Amazon (our link at left), you can also see this book at Minnis' website at http://web page .pace.edu/MMinnisbook
-  Septic Tank/Soil-Absorption Systems: How to Operate & Maintain [ copy on file as /septic/Septic_Operation_USDA.pdf ] - , Equipment Tips, U.S. Department of Agriculture, 8271 1302, 7100 Engineering, 2300 Recreation, September 1982, web search 08/28/2010, original source: http://www.fs.fed.us/t-d/pubs/pdfimage/82711302.pdf
-  Percolation Testing Manual, CNMI Division of Environmental Quality, PO Box 501304, Saipan, MP 96950
-  Septic System Owner's Manual, Lloyd Kahn, Blair Allen, Julie Jones, Shelter Publications, 2000 $14.95 U.S. - easy to understand, well illustrated, one of the best practical references around on septic design basics including some advanced systems; a little short on safety and maintenance. Both new and used (low priced copies are available, and we think the authors are working on an updated edition--DF. Quoting from one of several Amazon reviews: The basics of septic systems, from underground systems and failures to what the owner can do to promote and maintain a healthy system, is revealed in an excellent guide essential for any who reside on a septic system. Rural residents receive a primer on not only the basics; but how to conduct period inspections and what to do when things go wrong. History also figures into the fine coverage.
-  Test Pit Preparation for Onsite Sewage Evaluations, State of Oregon Department of Environmental Quality, Portland OR, 800 452-4011. PDF document. We recommend this excellent document that offers detail about soil perc tests, deep hole tests, safety, and septic design. Readers should also see Soil Percolation Tests and for testing an existing septic system, also see Dye Tests
-  Grass is Always Greener Over the Septic Tank, Bombeck, Erma: $ 5.99; FAWCETT; MM; This septic system classic whose title helps avoid intimidating readers new to septic systems, is available new or used at very low prices. It's more entertainment than a serious "how to" book on septic systems design, maintenance, or repair. Not recommended -- DF.
-  US EPA Onsite Wastewater Treatment Systems Manual Top Reference: US EPA's Design Manual for Onsite Wastewater Treatment and Disposal, 1980, available from the US EPA, the US GPO Superintendent of Documents (Pueblo CO), and from the National Small Flows Clearinghouse. Original source http://www.epa.gov/ORD/NRMRL/Pubs/625R00008/625R00008.htm
-  Water Wells and Septic Systems Handbook, R. Dodge Woodson. This book is in the upper price range, but is worth the cost for serious septic installers and designers. Quoting Amazon: Each year, thousands upon thousands of Americans install water wells and septic systems on their properties. But with a maze of codes governing their use along with a host of design requirements that ensure their functionality where can someone turn for comprehensive, one-stop guidance? Enter the Water Wells and Septic Systems Handbook from McGraw-Hill.
Written in language any property owner can understand yet detailed enough for professionals and technical students this easy-to-use volume delivers the latest techniques and code requirements for designing, building, rehabilitating, and maintaining private water wells and septic systems. Bolstered by a wealth of informative charts, tables, and illustrations, this book delivers:
* Current construction, maintenance, and repair methods
* New International Private Sewage Disposal Code
* Up-to-date standards from the American Water Works Association
-  Wells and Septic Systems, Alth, Max and Charlet, Rev. by S. Blackwell Duncan, $ 18.95; Tab Books 1992. We have found this text very useful for conventional well and septic systems design and maintenance --DF. Quoting an Amazon description:Here's all the information you need to build a well or septic system yourself - and save a lot of time, money, and frustration. S. Blackwell Duncan has thoroughly revised and updated this second edition of Wells and Septic Systems to conform to current codes and requirements. He also has expanded this national bestseller to include new material on well and septic installation, water storage and distribution, water treatment, ecological considerations, and septic systems for problem building sites.
-  The NSFC Products List has an excellent list of design manuals/modules available from their website or by telephone 800-624-8301
- Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
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- The HOME REFERENCE BOOK - the ENCYCLOPEDIA of HOMES, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume.
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