The Causes of Low Pressure in a Sprinkler System

Incorrect Operating Pressure of Sprinkler Heads

• The sprinkler head manufacturer usually provides charts that indicate the operating pressure of the heads. Spray heads have an operating pressure of about 25 to 30 pounds per square inch, rotor heads a 30 to 50 PSI range, and drip heads an operating pressure of about 20 PSI. The sprinkler head should be checked to ensure it is set at the recommended operating pressure.

Incorrect or Clogged Sprinkler Nozzle

• A nozzle is a projecting tube that is connected to the sprinkler head. It scatters the water over the lawn or landscape being irrigated. The volume of the water and the throwing distance are controlled by the nozzle. Nozzles have pattern and distance specifications that should be followed to ensure proper operation of the sprinkler system. When a nozzle is clogged or is already worn, it can change the spray pattern or reduce pressure, causing water not to reach the projected spray area.

Faulty Valve

• Irrigation control valves are devices that turn the sprinklers on and off, and can be either manual or automatic. Manual valves can be turned on and off using a handle, while automatic ones are managed by remote controls. Automatic systems generally operate by designing one valve to open after another is already completely closed. Two valves operating at the same time initiates a loss of pressure. This loss of pressure causes one valve to be only partially closed, resulting in water flow control problems.

Leaks in the Sprinkler System

• The most common sprinkler system leaks occur on the control valves. The presence of valve leaks can be determined by checking whether water flows from the sprinkler head even when the system is turned off. If water continues to seep to the head with the system off, this is a common indication that the control valves have leaks.