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Septic drop box or D-box leaks & flooding: this article explains the causes & suggests cures for effluent leaks, odors, or smells at the septic distribution 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.
Distribution Box Clogs, Flooding, Leaks & Odors: troubleshooting & repair
Reader Question: water is leaking out of my distribution box. Should the lid be sealed?
I have septic water leaking out of my distribution box. I the lid suppose to be sealed or does it just sit on top?? My system is is pumped up hill to a distribution box - Robert
Reply: water leaking into or out of a D-box is a sign of trouble that needs investigation and repair;
Water leaking out of the distribution box
If you see "water" leaking out of the septic drainfield D-box it's a sign of trouble. I suspect one of two typical causes.
The soils around the septic field may be saturated with groundwater, flooding the drainfield and backing up and out through the D-box cover. Just sealing the cover wouldn't fix anything in this case. You'd need to divert groundwater away from the drainfield.
The septic drainfield or leaching beds may be saturated from having become clogged - at end of life. If this is the case the backup of effluent is occurring because the soil is no longer absorbing effluent. You'll need to investigate to decide if the problem is a blocked or damaged or clogged drainfield line or if the whole field needs replacement.
Water leaking into the distribution box
You don't want surface or ground water leaking into the D-box since in any quantity that water will flood the drainfield. If the D-box cover fits pretty flush and smooth atop the distribution box, the amount of water that leaks in through the top should be trivial.
If the top is quite uneven and leaky, and if you can't correct surface drainage to keep water away from the distribution box you might need to add a compressible rubber or foam gasket between the D-box lid and the edges of the distribution box itself to reduce leaks there. Don't cement the distribution box lid in place or you won't be able to open it for inspection, adjustment, or repair.
Reader Question: leaks & odors at the D-box
7/12/2014 matt with the d box leak! said:
New septic put in 6 years ago. I have a pump chamber after my septic tanks (twin 750 gals), the chamber pump (100 or 150 gal ) kicks on when the level gets high enough. The grey water is pumped to my d- box about 25 feet. The d box has 2 outflow pipes leading to a leach field with baffles etc. The d box seems level and the problem is no matter what we have used to keep the cover on the box ( a piece of blue stone 1 " thick as it sits in the middle of a brick patio ) the d box leaks.
Again on the 4th of July with 12 -15 folks over ( part of my problem???) , I heard the pump chamber kick on, 15 seconds later could smell it and then about 3 to 5 ounces of water came out. The leaks came from the corners opposite the inflow. I can't get it to stop leaking, every time the pump chamber kicks on.
This is the 3 time in 6 years that I am faced with a dbox with a cover ( modified cover since its blue stone ) that leaks. If we cement the blue stone onto the d box how can this keep happening? Can the water just "eat" the concrete seal over a year? pls let me know by email when there is a response to my question - - many THANKS! email@example.com
Reply: how to check the distribution box flooding condition for an effluent pumping septic system design
You could convert to a more-easily sealed D-box but I don't think that's the problem. I suspect that the D-box is too small AND that with the small size, the effluent (it's not graywater) is not being accepted into the drainfield rapidly-enough. The result is the pump is filling the D-box faster than its outflow rate, causing backup and odor complaints.
A much larger D-box, sufficient to receive and then drain by gravity into the drainfields the whole pump cycle volume would be one approach that may tempt you but I don't recommend it.
Rather, you need to look at the inflow capacity of the drainfield - it may be that the drainfield is under-sized, or worse, that it is poorly designed / installed and is flooding, or possibly the line balancing openings in the D-box that balance flow into different drainfield lines are too small.
In sum, if you watch the D-box when the effluent pump cycles you'll probably see that around 125 gallons of effluent are surging into the D-box and overflowing it because the in-flow rate is faster than the outflow rate.\
If the D-box overflows only at the very end of the pump cycle you could see if your pumping system rate can be adjusted to send effluent to the D-box more slowly.
Reader Question: Clogged D-box Repair Procedures?
I have a system with a pump station that pumps gray water uphill about 50 yards. Today I noticed water percolating out of the ground near my drain field. I started digging and found what I assume is the d box. It was packed full of roots and the plastic seal around the pipe coming from the pump had been pushed out by the roots. I removed the roots but I could not remove the seal from the box. It has 5 more holes in it which 4 are closed and the other has a pipe leading to another concrete box 4-5 feet further out.
The second box is much deeper than the first. It appears that the pipes T out after the first box. More digging tomorrow. I ran the pump after replacing the lid and packing dirt around the pipe but it just came out of the box instead of going through the system. The downstream pipe is open.
Can the seal be replaced around the incoming pipe or should the box be replaced?
Do the other "boxes" typically have a lid like the first one does? I was wondering if I should dig them up and check for clogs.
The system is 9 years old and is pumped every year.
Thanks for any info and for this great website.
Kenneth M. 1/8/2012
Sure, if the D-box has become clogged by roots, and probably tipped and askew too, it needs to be cleaned, leveled, and the surrounding roots cut back to slow their re-invasion. Because you have just one pipe in and one pipe out of this D-box, and because you found a second deeper distribution box on your septic system, I suspect the first one is an access or inspection port and a connection between pipes, not much more.
Ultimately, presuming there is more than one leach line at your drainfield, there will be a D-box that distributes effluent among multiple lines - you'll want to find and check the condition of that device. The T-pipes you describe make it sound as if the septic installer forgot what the D-box was for but just stuck one in anyway. Too bad.
About the damaged seal on the first D-box, the choices are to replace the whole unit (this is not a costly part) or you could try cutting away the offending roots and digging around the pipe that enters or leaves the D-box, pouring concrete around the pipe at the outside of the D-box to try to get a decent seal.
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 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: firstname.lastname@example.org. 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
 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.
 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.
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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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