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How to fix a sprinkler system leak

We'll identify low head drain vs. a real leak, replace cracked heads, and tell you when to call a plumber.

How-to · Home plumbing
15–30 min
What you'll need
  • Replacement sprinkler head (if needed)
  • Thread sealant (if needed)
  • Shovel (if digging is needed)

At a glance

  • Determine if the leak is low head drain (normal) or a real leak.
  • Low head drain—water drains from the lowest head when the zone turns off—stops in minutes; no fix needed.
  • Replace a cracked or broken sprinkler head.
  • Tighten loose connections at the head or riser.
  • Call a plumber if water runs constantly when the zone is off (valve not closing).
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Steps

Goal: Identify low head drain vs. a real leak, fix cracked heads or connections, and know when to call a plumber.

  • Check if water stops within a few minutes of the zone turning off.
  • Good: Water stops—likely low head drain, normal. Bad: Water runs constantly—valve may not be closing. Call a plumber.

Identify leak type

Goal: Distinguish low head drain from a real leak.

  • Low head drain stops when the pipe empties. A real leak continues. Run the zone, turn it off, and watch.
  • Good: You know which you have. Proceed to Replace head if the head is cracked.
  • Bad: Water runs constantly when zone is off—call a plumber.

Replace head

Goal: Fix a cracked or broken sprinkler head.

  • Shut off the water. Unscrew the head. Install a new one that matches the flow rate and pattern.
  • Good: No drip when the zone runs.
  • Bad: Still leaks or water runs when zone is off—call a plumber.

When to get help

Call a plumber or irrigation specialist if:

  • Water runs constantly when the zone is off (valve not closing).
  • The leak is at the main line or valve box.
  • You cannot stop the leak by replacing the head.

Verification

  • No constant drip or flow when the zone is off (low head drain is OK).
  • Head and connections are dry when the zone is off.
  • Zone runs normally.

Reviewed by Blackbox Atlas

Frequently asked questions

Why does my sprinkler system leak?
Common causes: low head drain (normal), a cracked head, a loose connection, or a zone valve that does not close. Low head drain is not a leak—it is water draining from the pipes when the zone turns off.
Can I fix a sprinkler system leak myself?
Yes, for cracked heads and loose connections. Replace the head or tighten the fitting. If water runs constantly when the zone is off, the valve may not be closing—call a plumber.
When should I call a plumber for a sprinkler leak?
Call a plumber or irrigation specialist if water runs constantly when the zone is off (valve not closing), the leak is at the main line or valve box, or you cannot stop the leak by replacing the head.

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