Sprinkler pipes are buried, so a pipe leak usually shows up as wet or sunken ground, bubbling water or low pressure in a zone.
Pipe leaks can be on a zone’s lateral line, which leaks only while that zone runs, or on the mainline, which can leak all the time.
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Quick Answer
Sprinkler pipe leaks are commonly caused by roots, digging, freezing, age or failed fittings and joints. A leak that appears only while one zone runs is usually on that zone’s lateral pipe. A leak that continues with the system off is usually on the mainline and should be repaired promptly.
What You May Be Seeing
- Soggy or sunken ground
- Water bubbling from the soil
- Low pressure in a zone
- A spot that stays green or muddy
- A higher water bill
Water escaping from a buried pipe soaks the soil above it and reduces pressure to the heads downstream.
The First Question to Ask
Does the leak happen only while one zone runs, or all the time?
Only while a zone runs points to a lateral pipe. All the time points to the mainline or another pressurized pipe.
If It Leaks Only While a Zone Runs
The lateral pipe is likely.
Common causes include:
- Cracked lateral pipe: from roots, age or digging
- Failed fitting: at a tee or elbow
- Broken swing joint: under a head
If It Leaks All the Time
The mainline is likely.
Common causes include:
- Mainline crack: always pressurized
- Failed mainline fitting: before the valves
- Freeze damage: in cold climates
Leaks Near Trees
Roots can crack or crush pipes over time.
Leaks After Digging
Shovels, augers and edging can puncture buried pipe.
Repeated Leaks in the Same Area
Brittle or aging pipe may be failing in several places.
What You Can Check Yourself
- Run each zone and watch for wet areas
- Check whether the leak continues with the system off
- Look for sunken soil or bubbling
- Close the irrigation shutoff if water is flowing steadily
What a Technician May Test
- Zone isolation
- Pressure test
- Leak location
- Excavation and pipe repair
Most Common Causes
- Root damage
- Digging damage
- Freeze damage
- Aging or brittle pipe
- Failed fitting or joint
Repair or Replace?
Most pipe leaks are repaired by replacing the damaged section. Repeated leaks in old pipe may justify replacing a longer run.
When to Call a Sprinkler Professional
Call a professional if:
- The leak continues with the system off
- You can’t find the leak
- Soil is sinking
- The leak is near the foundation
Find a sprinkler repair pro or read our emergency shutoff guide if water won’t stop.
Related Sprinkler Problems
- How Do I Know If I Have an Underground Sprinkler Leak?
- Why Is My Sprinkler System Leaking?
- Why Is My Sprinkler Water Pressure Low?
- Can My Sprinkler System Cause a High Water Bill?
Related Repairs
Typical Repair Cost
What you pay depends on the cause, the parts and your area. See our Sprinkler Leak Repair Cost Guide for typical ranges. Prices vary, and only an on-site diagnosis can give you an actual quote.
Frequently Asked Questions
What causes sprinkler pipes to leak?
Roots, digging, freezing, age and failed fittings are common causes.
Is a mainline leak worse than a lateral leak?
Usually, because the mainline is pressurized all the time and can leak continuously.
Can I repair a sprinkler pipe myself?
Small repairs are possible for experienced DIYers, but finding the leak and working on pressurized lines is often better left to a professional.
How do I find where my sprinkler pipe is leaking?
Look for wet or sunken areas while each zone runs and with the system off.
Bottom Line
Leaking sprinkler pipes usually come from roots, digging, freezes, age or failed fittings.
A technician can isolate the line, find the leak and replace the damaged section.
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