New Jersey Administrative Code|Section 7:9A-11.3 - Construction requirements

                                                
 § 7:9A-11.3. Construction requirements 
 
(a) Seepage pits shall be constructed within an excavation affording adequate working space and shall be constructed of stone, brick, cinder, precast concrete or concrete block, or similar material laid dry with open joints where permeable strata has been penetrated, except that if the seepage pit is not of circular construction or if the surrounding ground is subject to cave-in, all horizontal joints shall be mortared in such a manner as to prevent structural failure. The following requirements shall be met: 
 
1. All joints above the inlet, in all cases, shall be made water-tight.
 
2. Before placement of backfill, all sidewall areas shall be scarified.
 
3. The bottom of the seepage pit shall be filled with coarse gravel to a depth of one foot unless the bottom is in a sand or gravel formation.
 
(b) Seepage pits shall be backfilled according to the following procedure: 
 
1. The space between the excavation and the seepage pit wall shall be backfilled with at least three inches of coarse gravel or filter material meeting the requirements of 7:9A-10.3(e)2.
 
2. Where cinder or concrete blocks are laid with core openings exposed, the space between the excavation and seepage pit wall shall be backfilled with at least six inches of two and one-half inch crushed stone or gravel.
 
3. Backfill above the inlet shall be as required for disposal fields in 7:9A-10.3(f)2 and shall be thoroughly compacted by hand or mechanical tamping methods. The use of heavy machinery for this purpose is prohibited.
 
(c) Covers shall be constructed of reinforced concrete, shall be a minimum of three inches in thickness, water-tight, and shall be designed and constructed so as not to be damaged by any load which is likely to be placed upon them.
 
(d) At least one access opening with a removable water-tight cover and a minimum dimension of 24 inches shall be provided. Access openings shall meet the following requirements:
 
1. Access shall be adequate to permit pumping out of the pit as well as inspection and maintenance of the inlet.
 
2. When the cover of the seepage pit is deeper than 12 inches below finished grade, the access opening shall be extended to within 12 inches of finished grade by means of a concrete riser with a cast-iron manhole cover.
 
3. When the access opening is below finished grade, a permanent marker at finished grade shall be provided to indicate its location.
 
4. When the access opening is at or above finished grade, the cover shall be bolted, locked or otherwise secured to prevent access by children.