Why One Sprinkler Head Works and the Rest Don’t

Sprinkler systems are a fantastic tool for keeping your lawn and garden lush and healthy, but they can be frustrating when they malfunction. One common issue homeowners face is when only one sprinkler head works while the rest in the same zone fail to operate properly. This problem can lead to uneven watering, dry patches, and an unhealthy lawn. Understanding the reasons behind this issue is key to diagnosing and fixing it. In this article, well explore the potential causes of why one sprinkler head works while others dont, along with practical steps to resolve the issue and prevent future problems.

Understanding Your Sprinkler System

Before diving into the causes, its helpful to understand how a sprinkler system works. Most systems are divided into zones, each controlled by a valve that directs water to a group of sprinkler heads. Each head is designed to distribute water evenly across a specific area. When one head functions but others in the same zone dont, the issue is likely related to water flow, pressure, or a specific component in the system. Lets explore the most common reasons for this problem.

Common Causes of One Sprinkler Head Working While Others Dont

Here are the primary reasons why one sprinkler head may be operational while the rest in the same zone are not, along with tips for identifying and addressing each issue.

1. Clogged Sprinkler Heads

One of the most common reasons for non-working sprinkler heads is clogging. Debris such as dirt, sand, grass, or small rocks can accumulate inside the sprinkler head, blocking water flow. If one head is clear while others are clogged, the clear head may function normally while the others fail to spray or pop up.

Signs to Look For: Inspect the non-working heads for weak or no water flow, irregular spray patterns, or heads that dont pop up fully. You may also notice debris around the head or in the filter.

What to Do:

• Turn off the water supply to avoid water loss.

• Unscrew the non-working sprinkler head and remove the filter (if applicable).

• Rinse the head and filter under clean water to remove debris.

• Check the nozzle for blockages and clear it with a small wire or pin.

• Reassemble and test the system to ensure proper operation.

2. Low Water Pressure

Low water pressure in a zone can prevent multiple sprinkler heads from functioning, but one headoften the one closest to the valve or water sourcemay still work due to its proximity. Low pressure can result from a variety of issues, including leaks, a partially closed valve, or an undersized water supply line.

Signs to Look For: Weak spray from multiple heads, heads that dont pop up fully, or only the head closest to the valve working properly.

What to Do:

• Check the zone valve to ensure its fully open.

• Inspect the system for visible leaks or soggy areas that might indicate an underground leak reducing pressure.

• Use a pressure gauge to measure water pressure at the sprinkler head. Most systems require 3050 PSI for optimal performance.

• If pressure is consistently low, consult a professional to evaluate whether the water supply line or pump is adequate for your system.

3. Broken or Damaged Sprinkler Heads

Physical damage to sprinkler heads, such as cracks or broken seals, can prevent them from functioning. Damage may occur from lawnmowers, foot traffic, or natural wear and tear. If one head is undamaged, it may work while the others fail.

Signs to Look For: Visible cracks, missing parts, or heads that dont retract properly. Water may leak around the base of the head instead of spraying.

What to Do:

• Inspect each non-working head for visible damage.

• Replace any broken heads with the same model to ensure consistent water distribution.

• Ensure the new head is installed at the correct height and angle to match the working head.

4. Faulty Zone Valve

The zone valve controls water flow to a specific group of sprinkler heads. If the valve is malfunctioningdue to debris, electrical issues, or wearit may not open fully, restricting water to most heads in the zone. The head closest to the valve may still receive enough water to function.

Signs to Look For: All heads in a zone (except one) fail to operate, or the zone doesnt turn on consistently. You may hear a humming sound from the valve box if its an electrical issue.

What to Do:

• Locate the valve box and inspect the zone valve for debris or damage.

• Check the solenoid (the electrical component that opens the valve) for loose wires or corrosion.

• Clean or replace the valve diaphragm if its clogged or damaged.

• If the valve is electrically controlled, test the wiring with a multimeter or consult a professional.

5. Underground Pipe Leaks or Breaks

An underground leak or break in the pipe can significantly reduce water pressure to downstream sprinkler heads, leaving only the head closest to the water source functional. Leaks can result from tree roots, freezing temperatures, or accidental damage during yard work.

Signs to Look For: Soggy or muddy areas along the pipe route, sinkholes, or a noticeable drop in water pressure in one zone. You may also hear hissing or gurgling sounds underground.

What to Do:

• Turn off the water supply to prevent further water loss.

• Inspect the yard for signs of leaks, such as wet spots or eroded soil.

• Run the affected zone and observe where water pools to narrow down the leaks location.

• Contact a professional irrigation specialist, as locating and repairing underground leaks often requires specialized tools like acoustic leak detectors.

6. Incorrect Sprinkler Head Design or Installation

If your sprinkler system was improperly designed or installed, the heads may not be compatible with the water pressure or flow rate of the zone. For example, one head may work because it requires less pressure, while others fail due??

System: to insufficient flow or mismatched head types.

Signs to Look For: Uneven spray patterns, heads that dont pop up or spray properly, or a mix of different head types (e.g., spray heads and rotor heads) in the same zone, which can cause inconsistent performance.

What to Do:

• Verify that all heads in the zone are the same type and model, as mixing types can lead to uneven water distribution.

• Check the manufacturers specifications for each head to ensure they match the systems water pressure and flow rate.

• If the system was recently installed or modified, consult the installer to confirm proper design. You may need to replace incompatible heads or adjust the zones layout.

7. Electrical or Controller Issues

If your sprinkler system is automated, an issue with the controller or wiring could prevent the zone from activating properly. This might allow one head to work if its receiving partial water flow, while others fail due to insufficient valve activation.

Signs to Look For: The controller displays error messages, the zone doesnt turn on as scheduled, or you hear no activation sound (e.g., a click) from the valve.

What to Do:

• Check the controller for error codes or programming issues.

• Inspect the wiring between the controller and the zone valve for loose connections or damage.

• Test the zone manually via the controller to see if it activates.

• If the issue persists, consult a professional to diagnose electrical problems.

8. Backflow Preventer or Main Valve Issues

The backflow preventer or main water valve supplies water to the entire sprinkler system. If its partially closed, clogged, or malfunctioning, it can restrict water flow to the zones, causing only one head (typically the closest to the water source) to function.

Signs to Look For: Reduced water flow across multiple zones or a noticeable decrease in system performance.

What to Do:

• Locate the backflow preventer or main valve and ensure its fully open.

• Inspect for debris or damage and clean if necessary.

• If the backflow preventer is faulty, contact a professional, as these devices often require specialized repair or replacement.

Steps to Diagnose and Fix the Problem

If youre dealing with one working sprinkler head and several non-working ones, follow these steps to pinpoint and resolve the issue:

1. Run a Zone Test: Activate the affected zone and observe which heads are working and which are not. Note any weak spray, failure to pop up, or leaks.

2. Inspect Sprinkler Heads: Check each non-working head for clogs, damage, or incorrect installation. Clean or replace heads as needed.

3. Check Water Pressure: Use a pressure gauge to measure water pressure at the working and non-working heads. Compare the readings to the manufacturers requirements.

4. Examine the Zone Valve: Locate the valve box and inspect the valve for debris, damage, or electrical issues. Clean or repair as necessary.

5. Look for Leaks: Inspect the yard for soggy spots, sinkholes, or other signs of an underground leak. Listen for hissing or gurgling sounds.

6. Test the Controller: If your system is automated, ensure the controller is programmed correctly and the wiring is intact.

7. Consult a Professional: If you cant identify or fix the issue, contact an irrigation specialist. They can use advanced tools to diagnose underground leaks or complex electrical problems.

Preventing Future Sprinkler Head Issues

Once youve resolved the issue, take steps to prevent it from happening again:

• Regular Maintenance: Schedule annual inspections to clean heads, check valves, and test system performance.

• Use Filters: Install inline filters to reduce debris entering the system.

• Winterize Properly: In cold climates, drain and winterize the system to prevent pipe damage from freezing.

• Avoid Physical Damage: Mark sprinkler head locations to avoid damaging them during lawn maintenance.

• Monitor System Design: Ensure all heads in a zone are compatible and the system is designed for your water pressure and flow rate.

When to Call a Professional

While some issues, like clogged heads or minor valve adjustments, can be handled by homeowners, others require professional expertise. Call an irrigation specialist if you encounter:

• Suspected underground leaks or pipe breaks.

• Persistent low water pressure across multiple zones.

• Electrical issues with the controller or solenoid.

• Complex system design problems or incompatible components.

A professional can use tools like leak detectors, pressure testers, and pipe locators to quickly identify and fix the problem, saving you time and preventing further damage.

Conclusion

When one sprinkler head works but the rest in the same zone dont, the issue could stem from clogged heads, low water pressure, damaged components, or problems with the zone valve, pipes, or controller. By systematically diagnosing the problemstarting with the sprinkler heads and working your way to the valve and water supplyyou can identify the cause and restore your systems performance. Regular maintenance and prompt repairs are essential to keeping your sprinkler system running smoothly, ensuring your lawn and garden stay healthy and vibrant. If the problem persists or seems complex, dont hesitate to call a professional to get your system back on track.