New Jersey Administrative Code › Title 7 - ENVIRONMENTAL PROTECTION › Chapter 9A - STANDARDS FOR INDIVIDUAL SUBSURFACE SEWAGE DISPOSAL SYSTEMS › Subchapter 9 - EFFLUENT DISTRIBUTION NETWORKS › Section 7:9A-9.4 - Distribution boxes

Current through Register Vol. 56, No. 14, July 15, 2024
(a) A distribution
				box shall be required for all gravity flow systems and all gravity dosing
				systems where the effluent shall be distributed between two or more separate
				distribution laterals. The following requirements shall be met:
1. Distribution boxes shall be water-tight
				and constructed of sound and durable materials which will resist decay or
				corrosion by sulphuric acid, frost damage, cracking or buckling due to
				backfilling or other anticipated stresses.
2. The distribution box shall be set
				perfectly level and shall be installed as follows:
i. In the case of disposal beds, the
				distribution box shall be installed directly on the filter material within the
				disposal bed.
ii. In the case of
				disposal trenches, the distribution box shall be set on a layer of gravel or a
				concrete footing extending downward below the maximum expected depth of frost
				penetration. Where gravel is used, the gravel shall extend laterally a minimum
				of six inches beyond the sides of the distribution box.
3. A separate outlet shall be provided for
				each distribution lateral. The inverts of all outlets shall be securely set at
				the same level which shall be a minimum of two inches above the bottom of the
				box. When installation is complete the distribution box shall be filled with
				water at which time the installation shall be checked to make sure that it is
				level. Adjustments shall be made as necessary so that all outlets are
				permanently and securely fixed at exactly the same elevation prior to
				backfilling.
4. The invert of the
				inlet shall be at least one inch above the invert of the outlets. Where dosing
				is employed, or where the connecting pipe from the pre-treatment unit has a
				steep slope, measures shall be taken to prevent direct flow of effluent across
				the distribution box resulting in unequal distribution of effluent among the
				distribution box outlets. This may be accomplished by installation of a baffle
				or elbow within the distribution box or by use of two distribution boxes
				connected in series. In the latter case, all outlets of the first distribution
				box shall be sealed off except for the outlet which discharges to the second
				distribution box.
5. Distribution
				boxes shall be provided with a means of access which may be a removable lid in
				the case of smaller boxes. Access to larger boxes may be provided by means of
				manholes and inspection ports with removable water-tight covers. In any case,
				the following requirements shall be met:
i.
				Access openings must be adequate in size and located to facilitate removal of
				accumulated solids and inspection of the inlet and all outlets.
ii. All access openings shall be extended to
				within 12 to 18 inches of the finished grade surface.
iii. Access openings shall be constructed in
				such a manner as to prevent the entrance of surface water.