Stop the Bang: Understanding and Preventing Water Hammer in Irrigation Systems

If your customer says, “It sounds like a hammer hitting the pipes when the system shuts off,” they’re not exaggerating.

That bang you hear? That’s water hammer, and it can do real damage to valves, fittings, and customer relationships if you’re not proactive.

In this guide, we’ll break down what water hammer is, how to spot it, and how to stop it before it stops you from getting paid.

What Is Water Hammer in Irrigation?

Water hammer occurs when a sudden stop or change in water flow causes a shockwave through the system. It’s especially common in irrigation when valves close too quickly, forcing pressurized water to crash against the end of a pipe.

Think of it like this: You’re driving fast and slam the brakes. The momentum keeps pushing forward. That’s what water is doing, slamming into fittings, emitters, and valves.

How to Tell If It’s Water Hammer

Your customer may not use the term water hammer, but here’s what they’ll likely say:

• “The pipes rattle when the sprinklers shut off.”
• “It sounds like a thud or a bang when the system turns off.”
• “There’s a loud knock near the valve box.”
• “My sprinkler heads keep blowing off.”

These are all red flags; left untreated, they can lead to:

• Cracked fittings
• Damaged valves
• Leaking heads
• Customer callbacks

Common Causes of Water Hammer in Irrigation

Contractors commonly experience water hammer from:

• Fast-closing solenoid valves
• Excessively high pressure
• Long straight pipe runs with no air cushions
• Air trapped in the system
• Incorrectly sized pipes or valves

How to Prevent Water Hammer in Your Installs

There’s no one-size-fits-all fix, but there are several strategies to prevent water hammer and keep your system running smoothly:

#1: Use Slow-Closing Valves

The Champion CIP-100IV Inline Valve features a slow-closing diaphragm, designed to reduce the abrupt shutoff that causes water hammer.

Bonus: It’s equipped with:

• Waterproof 24V AC solenoid
• Internal filtration to prevent debris buildup
• Fail-safe normally closed design
• Pressure range of 15 to 145 PSI

[Click here to learn more about our inline valve]

#2: Add Air Chambers or Surge Arrestors

In more extreme cases, especially commercial installs, use dedicated air chambers or hydraulic arrestors near valves or backflow devices.

#3: Prevent Air Traps

Always install a proper automatic drain valve or manual air release valve in systems prone to air entrapment.

#4: Size Valves and Pipes Correctly

Oversizing or undersizing can create flow instability. Champion offers valves from 3/4″ to 2″ to fit everything from residential zones to large commercial turf areas.

Final Thoughts

Don’t wait for the bang.

Water hammer isn’t just annoying, it’s destructive. By proactively installing Champion’s CIP-100IV and pairing it with smart system design, you can stop water hammer before it starts and keep your customers coming back, without callbacks.

Shop the CIP-100IV Inline Valve here or contact your local wholesaler to add it to your next install.