Valve Box Full of Water?
It Could Be a Bad Diaphragm

If your sprinkler valve box is full of water, one common cause is a leaking valve diaphragm. The diaphragm is the rubber part inside the valve that opens and closes when the system turns on and off. In the Treasure Valley where systems run hard all summer and then sit through an Idaho winter, diaphragms wear out faster than most homeowners expect.

What Causes It

When the diaphragm wears out, tears, or gets debris stuck in it, the valve may leak constantly. The solenoid — the electrical component that tells the valve to open and close — can also fail and stick the valve open. Either way, water ends up sitting in the box when it should not be.

• Worn or torn valve diaphragm letting water bleed through constantly
• Failed solenoid stuck in the open position
• Debris caught in the valve seat preventing a full seal
• A zone that runs continuously even when the controller is off

What Happens If You Ignore It

Left alone this wastes water, drives up your utility bill, and can eventually cause the valve to fail completely. You might also notice a zone that will not fully shut off, or sprinkler heads that trickle even when the system is supposed to be off. These are all signs the valve needs attention.