Quick Answer
To seal off a well and prevent contamination, a well casing should be completely surrounded by a concrete or steel sleeve, and the area around the well should be filled with concrete to prevent surface water from seeping in. The well casing should also be sealed at the top with a well cap or seal to prevent entry points for animals or debris. A properly sealed well ensures safe and clean water access.
Sealing the Well Casing
When sealing a hand-dug well, it’s essential to use a concrete or steel sleeve that surrounds the entire well casing. This sleeve should extend at least 12 inches below the bottom of the well and 6 inches above the ground surface. A good rule of thumb is to use a minimum of 4 inches of concrete around the sleeve for effective sealing. For a 6-inch well casing, this translates to a 24-inch diameter concrete sleeve, which can be achieved with a 24-inch diameter steel or PVC pipe.
Concrete Sealing Techniques
To ensure a tight seal, the concrete around the well should be tamped and vibrated to eliminate air pockets. A minimum of 6 inches of concrete should be poured to cover the entire area around the well. The concrete should be allowed to set and cure for at least 28 days before the well is used for drinking water. It’s also essential to seal any cracks or gaps in the concrete with a water-based epoxy or cement patching compound.
Sealing the Well Cap
The well cap or seal should be securely attached to the top of the well casing using a steel or PVC pipe clamp. The cap should be at least 1 inch above the ground surface to prevent water from accumulating around the well. The cap should also have a secure lid or hatch that can be opened for maintenance or inspection. A rubber or silicone gasket should be used to seal the lid or hatch to prevent water and debris from entering the well.
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