Minimum size for a greywater storage tank?

Greywater Storage Tank Sizing Considerations

When designing a greywater storage tank system, consider the minimum tank size required to capture a significant portion of the household’s greywater flow. A general rule of thumb is to size the tank based on the total household water usage, but subtract the amount of rainwater harvesting and other non-greywater sources.

Typical Greywater Generation Rates

The typical greywater generation rate for a small household is around 30-50 gallons (114-189 liters) per day. However, this can vary greatly depending on household size, water usage habits, and appliance efficiency. For example, a family of four might generate 60-80 gallons (227-303 liters) of greywater per day.

Storage Tank Requirements

In addition to the minimum tank size, consider factors such as tank material, shape, and location. The tank should be made of durable, corrosion-resistant materials such as steel or fiberglass, and should be located in a well-drained area to prevent waterlogging. The tank should also be sized to accommodate the peak greywater flow rate, which can occur during peak water use periods such as washing dishes or taking showers. A general rule of thumb is to size the tank based on the 2-minute peak flow rate, which can be estimated using the household’s water usage patterns.