InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website. In this article series about septic system drop boxes we describe the best design of water distribution system pdf for locating and inspecting, repairing or replacing the septic drainfield distribution box, or the “D-box” or “Splitter box”.
Inspection and Reporting the Condition of Private Residential Waste Disposal Systems – or – Where Does it Go When I Flush? 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. How to Find the Septic System D-Box Question: distance from the septic tank to the D-box? How far away from the septic tank is the dbox?
How far from the main tank is the D box located on average? 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. 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. All outlets from the distribution box shall be at the same level to insure the even distribution of flow. 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. The drop between inlet and outlet inverts shall be at least two inches. 2 inch per foot or when siphon dosing is used. 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. 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. 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. Septic D-Box Piping Question: are the pipes from the D-box solid or perforated? Reply: It depends on septic drainfield layout.
Signs of D-Box Trouble, Advice on D-Box Repairs 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. Reader Question: water is leaking out of my distribution box. Repair Question: How to repair a bad D-box lid or cover My D box lid has failed and the sides are starting to crumble. Temporary D-Box Repairs – eliminate the D-box? 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. Septic System D-Box Splitters – Drainfield Resting 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. Continue reading at SEPTIC D-BOX INSPECTION or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below. SEPTIC D-BOX PIPING – solid vs. 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.