Benefits of Covering a Concrete Cistern with Soil — Is It Worth It?

Insulation and Temperature Regulation

Covering a concrete cistern with soil can reduce temperature fluctuations within the cistern. When soil is in contact with the concrete, it acts as a natural insulation layer, keeping the water inside the cistern cooler in the summer and warmer in the winter. This can help to slow down bacterial growth and reduce the risk of contamination.

Reduced Evaporation and Maintenance

Soil covering can also reduce water evaporation from the cistern surface, which is particularly important for off-grid systems where water is scarce. Additionally, a soil-covered cistern requires less maintenance, as the soil prevents algae growth and reduces the need for frequent cleaning. For a 1000-gallon cistern, covering it with 2-3 feet of soil can reduce evaporation by up to 50%.

Design and Construction Considerations

When designing a soil-covered cistern, it’s essential to consider the drainage and filtration systems. A minimum of 1-2 inches of soil space between the soil surface and the cistern lid is recommended to prevent waterlogging and clogging. Additionally, a French drain or perforated pipe can be installed at the bottom of the cistern to facilitate drainage and prevent water from accumulating at the bottom of the cistern.