Sealing a Dug Well and a Sand Point Near a Septic System
A developer is redeveloping a 0.75-acre parcel and plans a new septic system. Two old wells are found: a 24-inch-diameter brick-lined dug well 18 ft deep, with water at 12 ft, and a 2-inch driven sand-point well 35 ft deep located 12 ft from the proposed septic trench. The dug well is 20 ft from the house foundation and has an old hand pump and debris in the bottom. The sand point has no casing above grade. The contractor proposes to fill the dug well with fieldstone and sand to grade, and to dump 50 lb of bentonite pellets into the sand point, then cover both with topsoil. No permit application has been filed. Public water is available at the street.
1. Identify the regulatory and technical deficiencies in the contractor’s plan.
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The plan fails both regulatory and technical tests. Well abandonment in New Jersey requires a permit and a licensed well driller; the contractor cannot simply bury the wells. Fieldstone and sand are permeable and do not seal the borehole; they can transmit surface water and septic effluent. Bentonite pellets dumped into a 2-inch sand point will likely bridge and leave the lower casing unsealed. Covering with topsoil hides the problem. In addition, the sand point is only 12 ft from the proposed septic trench, so any open pathway is a direct contamination risk. The dug well’s brick liner and debris must be addressed, not just filled. File the abandonment permit, use proper materials, and document the work.
2. Specify the sealing procedure for the dug well and the sand point.
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Dug well: remove the pump, debris, and any contaminated material; disinfect; remove the top of the brick liner to below grade if required; fill the lower portion with clean, graded fill or grout as approved, and seal the upper portion with a continuous low-permeability grout (neat cement or bentonite) from the bottom up or by tremie. Do not use fieldstone. Sand point: if the casing can be pulled, pull it and grout the resulting hole; if it cannot, drive a tremie to the bottom and pressure-grout the casing, then cut the casing off below grade. Use grout, not pellets. Verify volumes and keep the top seal intact.
3. What records and verification would you provide to close out the abandonment?
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Provide the NJ well abandonment report, the original or reconstructed well log, GPS coordinates, diameter and depth, materials used, grout mix and volume, any footage of casing removed, before/after photographs, and the date. Have the local health department or NJDEP inspect if required. Record that both wells were sealed and that no surface opening remains. Keep copies for the owner and the driller. This protects the developer and confirms the septic separation issue was resolved.