Quick Answer

Most sprinkler system problems, such as a zone not turning on or low pressure, can be resolved by checking the water supply, inspecting the mainline for visible damage, cleaning clogged sprinkler heads, or adjusting the controller settings. Often, a simple adjustment or minor repair can restore your system to full operation.

The Problem

You head outside to see your lawn getting watered, but one zone isn't working, or perhaps the water pressure is so low it's barely dribbling out. A malfunctioning sprinkler system can lead to dry patches in your lawn, wasted water, and even higher water bills if a leak goes unnoticed. Before calling a professional, many common issues can be diagnosed and fixed with basic tools and a little know-how.

Step-by-Step Fix

Safety Note: Always turn off the main water supply to your sprinkler system before attempting any repairs to prevent accidental activation or water leaks.

Step 1: Check the Water Supply

Ensure your main water shut-off valve for the irrigation system is fully open. Sometimes, it can be partially closed, leading to low pressure across all zones. Also, check for any recent utility work in your area that might affect water pressure.

Step 2: Inspect the Controller (Timer)

Verify that your sprinkler controller is set to the correct date and time, and that the program is active. Check for any "rain delay" or "off" settings that might be preventing the system from running. Replace the backup battery in the controller if it's old, as a weak battery can cause intermittent issues.

Step 3: Identify the Problematic Zone or Head

Run your sprinkler system manually, zone by zone. This will help you pinpoint whether the issue is system-wide or isolated to a specific zone or individual sprinkler head.

Step 4: Examine Sprinkler Heads for Clogs or Damage

If a specific head isn't working, gently pull up pop-up heads to inspect for debris (dirt, grass clippings) or physical damage. Clean out any visible clogs with a small brush or needle. If the head is cracked or broken, it will need to be replaced.

Step 5: Check for Leaks in the Mainline or Lateral Lines

Look for unusually wet spots in your yard, particularly between the valve box and the malfunctioning sprinkler heads. A leaking pipe will reduce pressure to the downstream heads. While minor surface leaks might be visible, most leaks are underground and require more extensive troubleshooting.

Step 6: Troubleshoot Valve Issues

If an entire zone isn't working, the problem likely lies with the zone valve. Turn off the main water supply. Carefully open the valve box and inspect the wiring for any loose connections or corrosion. Manually activate the solenoid by turning it a quarter turn counter-clockwise. If the zone turns on, the electrical signal from the controller might be the issue. If it doesn't turn on, the diaphragm inside the valve might be torn or the solenoid itself could be faulty and require replacement.

Common Causes

• Clogged Sprinkler Heads: Dirt, sand, and debris can easily block the nozzles.
• Low Water Pressure: Partially closed main shut-off valves, leaks, or municipal water supply issues.
• Faulty Controller/Timer: Incorrect programming, dead backup battery, or electrical issues.
• Damaged Pipes or Heads: Physical damage from lawnmowers, foot traffic, or freezing temperatures.
• Malfunctioning Zone Valves: Worn diaphragms, faulty solenoids, or electrical wiring problems.

Tips & Prevention

• Regular Inspections: Periodically run your system to check for odd behavior, leaks, and clogs.
• Winterization: In colder climates, properly winterize your system to prevent pipes and heads from freezing and cracking.
• Clean Regularly: Clean sprinkler heads as needed to prevent mineral buildup and clogs.
• Proper Mowing: Be careful when mowing around sprinkler heads to avoid physical damage.

When to Call a Professional

While many minor issues can be DIY-fixed, call a licensed irrigation specialist if you suspect a major underground leak, have persistent low pressure throughout your system that you can't diagnose, or if electrical troubleshooting of the controller and valves is beyond your comfort level. Professionals have specialized tools to locate underground leaks and repair complex electrical issues safely and efficiently.