How to calculate the required tank size for a household?

Determining Water Usage

To calculate the required tank size, first determine the average daily water usage of the household. In the United States, the average household water usage is around 80-100 gallons per day. However, this number can vary depending on the size of the household, number of occupants, and their water-intensive habits. Use the following formula: Total Daily Water Usage (TDWU) = (number of occupants x 50 gallons/occupant) + additional water usage for appliances, gardens, and other purposes.

Calculating Tank Size

Once you have determined the TDWU, add a 10-20% reserve to account for unexpected water usage spikes and to ensure a safe water supply during periods of low water production or high demand. For example, a household with 4 occupants and an additional 20 gallons/day for appliances and gardens would have a TDWU of 260 gallons/day. Adding a 15% reserve, the household’s required tank size would be 298 gallons. The next available tank size should be selected, which in this case would be a 300-gallon tank.

Selecting the Right Tank

When selecting a tank, consider its pressure rating, which is usually measured in pounds per square inch (PSI). The required pressure rating depends on the water supply system’s pressure and the household’s elevation. A general rule of thumb is to select a tank with a pressure rating 2-5 PSI higher than the system’s pressure. Additionally, ensure the tank is designed for the household’s climate and is constructed from durable materials to withstand corrosion and extreme weather conditions.