The first cow (horse or bison) in line gets water on the 4th stroke (with the pendulum on the front position of the hood and the drain hole at 5 feet). It takes 2½ minutes for the water to drain down to the this drain hole level. Those drinking within that time do not need to replenish this water. Once the livestock know the water is there, they will pump until it comes up. For summer and/or training periods when there isn't freezing temperatures, the drain hole can be taped off and the livestock will get water immediately.