Counterflow towers                               are designed so that air flows vertically upward, counter to the flow of falling water in the fill.

Because of this vertical airflow, it is not possible to use the open, gravity-flow basins typical in crossflow designs. Instead, counterflow towers use pressurized, pipe-type spray systems to spray water onto the top of the fill.

Since air must be able to pass through the spray system, the pipes and nozzles must be farther apart so as not to restrict airflow.