Quick Answer
To build a concrete cistern for long-term use, start by selecting a suitable location with adequate drainage, then dig a hole to the desired depth, and construct a concrete form using 2x6 or 2x8 lumber. Pour the concrete, ensuring proper compaction and finishing techniques. Allow the concrete to cure for at least 28 days before filling the cistern with water.
Site Selection and Preparation
A well-designed cistern requires a suitable location with adequate drainage and a level surface. Choose a spot that is at least 10 feet away from any potential water sources, such as a septic system or nearby water table. Before digging, mark out the cistern’s dimensions and excavate the area using a backhoe or shovel. The hole should be about 6 inches deeper than the desired cistern depth to allow for a 4-inch thick concrete slab at the bottom.
Concrete Form and Construction
Construct a concrete form using 2x6 or 2x8 lumber, depending on the desired cistern size. The form should be at least 4 inches taller than the cistern to allow for a finished top slab. Use a level to ensure the form is perfectly level and secure it with stakes and wire. Pour the concrete, starting with the bottom slab, and use a hand tamper or plate compactor to compact the concrete as it sets.
Finishing and Curing
Finish the cistern with a smooth, even surface using a bull float or trowel. Apply a concrete sealer to protect the cistern from water damage and extend its lifespan. Allow the concrete to cure for at least 28 days before filling the cistern with water. During this time, keep the cistern covered with a tarp or plastic sheet to prevent contamination and maintain humidity.
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