Quick Answer
To properly winterize a buried concrete cistern, it's essential to ensure the water inside is drained, the cistern is sealed, and the surrounding soil is compacted to prevent frost heave. This will prevent damage to the cistern and ensure its longevity. Regular inspections are also crucial.
Preparation and Draining
Before winterization, inspect the cistern for any debris, sediment, or contaminants. Drain the water completely using a submersible pump or a sump pump. The American Water Works Association recommends draining the cistern to a depth of at least 12 inches below the bottom of the inlet pipe.
Sealing and Compacting
Seal any openings or gaps in the cistern, including the inlet and outlet pipes, using a durable sealant like epoxy or polyurethane. Compact the surrounding soil to a depth of at least 12 inches to prevent frost heave. This will also help to prevent the cistern from shifting or settling unevenly.
Maintenance and Inspection
Regularly inspect the cistern and its surroundings to ensure the sealant remains intact and the soil remains compacted. Every 6-12 months, drain the cistern and inspect the interior for any signs of damage or erosion. Consider installing a frost-proof inlet and outlet system to further protect the cistern from freezing temperatures.
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