What is the minimum amount of water that should be kept in a firefighting tank?

The minimum amount of water that should be kept in a firefighting tank is considered to be 100 gallons. This amount is widely regarded as sufficient to provide an initial attack on small fires, particularly in wildland urban interface (WUI) areas where access may be limited and rapid response is critical. Having at least 100 gallons ensures that firefighters can engage effectively in suppression tactics without the immediate need for resupply.

While smaller quantities, such as 50 gallons, may not provide enough capacity to manage even the initial stages of a fire, significantly larger amounts than 100 gallons, such as 150 or 200 gallons, can be optimal but may not be necessary for all firefighting scenarios. The focus on maintaining a minimum of 100 gallons strikes a balance between readiness and practical resource management in various firefighting operations.