What is a significant limitation of using a single portable water tank?

A significant limitation of using a single portable water tank is that it can only handle low overflow rates. When water is being delivered or transferred to and from the tank, a single tank may not have the capacity to accommodate high flow rates, which can lead to overflow or delays in water supply during critical operations such as firefighting. This limitation can impact the efficiency and effectiveness of water utilization in emergency scenarios, as a rapid water supply can be essential in controlling fires or managing other urgent situations.

In contrast, the other options do not directly relate to the functional limitations of a single portable water tank in terms of overflow rates. For example, while transportation and maintenance costs may be relevant, they do not affect the immediate ability of the tank to handle high-volume water usage.