Suction limits for jet pumps — what should I know?

Understanding Suction Limits

Jet pumps rely on the Venturi effect to create a pressure difference that drives water up from a water source. The suction limit is determined by the pump’s ability to maintain a sufficient pressure difference while overcoming the resistance of the water column. In general, a 25-foot suction limit is typical for shallow water wells with low water viscosity.

Factors Affecting Suction Limits

Factors that can affect jet pump suction limits include the pump’s design, the water’s viscosity, and the presence of air or gas bubbles in the water. A water well with high viscosity or air content can reduce the suction limit, while a pump with a high-performance design can extend the suction limit. For example, a well with a water viscosity of 1 cP (centipoise) might have a suction limit of 30 feet, while a well with 2 cP viscosity might have a suction limit of 20 feet.

Selecting a Jet Pump for a Shallow Water Well

When selecting a jet pump for a shallow water well, it’s essential to consider the suction limit and the pump’s compatibility with the water source. A pump with a suitable suction limit and a high-performance design can ensure reliable operation and prevent damage to the pump or the well. For example, a pump with a suction limit of 35 feet and a design pressure of 100 psi (pounds per square inch) might be suitable for a shallow water well with a 25-foot static suction.