Quick Answer
To calculate the volume for a cistern tank, use the formula Volume (in gallons or liters) = Length (in feet or meters) x Width (in feet or meters) x Height (in feet or meters).
Calculating Cistern Tank Volume
When sizing a cistern tank, it’s essential to consider the roof catchment area, rainfall intensity, and desired storage capacity. A general rule of thumb is to provide 1,000 to 1,500 gallons of storage per 1,000 square feet of roof catchment area. This assumes an average rainfall intensity of 1 inch per hour.
Factors Affecting Cistern Tank Volume
Other factors to consider when calculating cistern tank volume include the number of household members, irrigation requirements, and potential for water usage spikes. For example, a family of four with a small garden may require a 5,000-gallon cistern, while a larger family with multiple irrigation sources may require a 10,000-gallon tank. It’s also essential to consider the size and shape of the cistern tank, as a larger tank with a smaller footprint can be more space-efficient.
Cistern Tank Shape and Size Considerations
When designing a cistern tank, consider using a rectangular shape with a length of 6 to 8 feet and a width of 3 to 4 feet. This size range provides a balance between space efficiency and ease of maintenance. For example, a 6x4x4 foot cistern tank would have a volume of 96 cubic feet, equivalent to approximately 720 gallons. Using a cylindrical shape, on the other hand, would require a larger diameter and height to achieve the same volume, potentially increasing the tank’s footprint and construction costs.
Find more answers
Browse the full Q&A library by topic, or jump back to the topic this question belongs to.