Sizing a water storage tank involves calculating your water needs and the anticipated time you'll need to store water. A simple method uses your daily water consumption and the expected dry period.
Determining the right size for a water storage tank is crucial for ensuring a reliable water supply, whether for residential, agricultural, or commercial use. While several factors influence the ideal size, a fundamental approach involves estimating your water demand and the duration for which you need storage.
The Simple Formula
According to information from Bushman Tanks, one straightforward method to determine the appropriate size of a water tank is to use the following formula:
Tank Size = Average Daily Water Usage × Number of Days Between Rainfalls
This formula provides a baseline volume needed to cover your water requirements during periods without replenishment from rain (or other sources).
Breaking Down the Formula
Let's look at the components of this simple calculation:
- Average Daily Water Usage: This is the total amount of water used by your household, farm, or facility on an average day.
- Factors influencing this include:
- Number of people
- Appliances (toilets, showers, washing machines)
- Irrigation needs (gardens, livestock)
- Other specific uses (e.g., pools, washing vehicles)
- You can estimate this by reviewing past water bills or calculating based on typical usage patterns.
- Factors influencing this include:
- Number of Days Between Rainfalls: This refers to the longest expected period without significant rainfall or the frequency with which your tank will be refilled from your water source.
- This number depends on your local climate and weather patterns.
- Consider historical data or local knowledge about dry spells.
Practical Application & Example
Using the formula is straightforward once you have estimates for your daily usage and the dry period length.
Example:
Imagine a household with an estimated average daily water usage of 400 litres. If the expected longest period between significant rainfalls is 30 days, the required tank size would be:
Tank Size = 400 litres/day × 30 days
Tank Size = 12,000 litres
Therefore, a tank with a capacity of at least 12,000 litres would be a good starting point based on this simple calculation.
Other Factors to Consider
While the simple formula provides a basic estimate, other factors should be considered for a more precise sizing:
- Catchment Area: If collecting rainwater, the size of your roof or collection surface and local rainfall intensity will impact how quickly your tank refills.
- Intended Use: Is the water for emergency backup, full household supply, or irrigation only?
- Available Space: The physical area available for the tank installation.
- Budget: Tank sizes vary in cost.
- Future Needs: Anticipating changes in usage (e.g., growing family, expanding garden).
Using the simple formula from Bushman Tanks as a starting point, combined with consideration of these additional factors, will help you determine the most suitable water tank size for your specific needs.
