Why are traditional waterbowls so shallow?
It is normal and natural for an animal to drink or eat from a deep pail or trough. So why are all common waterbowls so shallow. Is there any benefit to a shallow waterbowl? The original shallow waterbowl was designed in 1923 when pressurized water systems became popular. Installing piping and waterbowls was expensive so the vast majority of farms utilized 1 waterbowl shared between 2 cows. This means that the waterbowl had to be situated between the stall dividers so that both cows could have access to the same bowl. Waterbowls had to be shallow to provide some space above the rim for the cows to fit their head. This shallow design did not consider how easy it would be for a cow to splash water out over the rim of the bowl. At the time, feed, bedding and labour were abundant, but waterbowls were a new expensive luxury.

Why do traditional waterbowls keep the water level so close to the top of the bowl?
When the water level is within 1 inch of the rim it is easy for a cow to lick and splash water over the top. Common sense would say provide as much space as possible to contain the splashes. Most countries have regulations that require that public water sources have protection from contamination. Traditional waterbowls meet the regulations by allowing an air space between the valve opening and the rim of the waterbowl to prevent water in the bowl being siphoned back up the water line. Unfortunately, in doing so it also allows the cows to fill the waterbowl right up to within an inch of the rim. Many simple methods would prevent the chance of backflow and still allow a higher rim to stop splashover. The best for livestock applications is a vacuum breaker that lets air enter the system instead of letting water siphon out of the waterbowls. (Link to backflow prevention website)

Waterbowl manufacturers have recognized that water splashed out of their waterbowls is a major concern with farmers, but their attempts to solve the problem have not been successful. Add on springs were designed to sit over the water to inhibit lapping. Add on extensions were designed to catch some of the lapping but were too wide and allowed most splashing to escape. Both devices were difficult to keep in place and were regularly knocked off. Recently some manufacturers have tried to address the splashing problem by curving the rim of the shallow bowl inward. They claim that these waterbowls are “non splash” The rim is meant to inhibit the cows splashing habits. Although slightly deeper it still allows the water level up near the top where it is easily lapped over the curved rim. One manufacturer has extended the rigid bowl of an existing design higher and wider, but splashes can still escape.