How Do You Troubleshoot Sprinkler System Problems?
Most sprinkler system problems fall into four categories: zones that do not turn on, heads that do not work correctly, coverage problems, and water pressure issues. Here is how to diagnose each.
Zone Does Not Turn On
When a zone does not activate from the controller: first, manually activate the valve (most valves have a manual bleed screw — open it slightly and the zone should activate regardless of the controller). If the zone activates manually but not from the controller: the wiring between the controller and the valve solenoid has a break or a poor connection. If the zone does not activate manually: the valve itself has failed (the diaphragm is torn, the solenoid has burned out, or the valve is clogged with debris). Valve solenoid replacement: $15 to $30 in parts, 20 minutes. Diaphragm replacement: $10 to $20 in parts, 20 minutes. Full valve replacement: $20 to $50 in parts, 30 to 60 minutes.
Broken Head or Geyser
A head spraying in all directions (a geyser): the head body has cracked (from a lawn mower, vehicle, or foot traffic). Shut off the zone and replace the head. A head that sprays in only part of its pattern: the nozzle is clogged or the arc adjustment has shifted. Remove the nozzle, clean it under running water, and reinstall. A head that does not retract after the zone turns off: dirt is preventing the spring from pushing the riser back down. Flush the head by cupping your hand over it while the zone runs and then letting it go quickly, which creates a flush of high-velocity water through the body.
Coverage and Pressure Problems
Brown, dry areas in the lawn after a full irrigation cycle: indicate coverage gaps (head spacing is too wide, a head is tilted, or a head has failed). Walk the zone while it runs and identify any heads that are not performing. Low pressure affecting all heads in one zone: a partially closed valve, a filter screen clogged with debris at the zone valve inlet, or a leak in the lateral pipe reducing pressure at the heads. Low pressure affecting all zones: a partially closed main supply valve or low service pressure from the utility.
Working With a Contractor on This Project
Getting the right outcome on any home services project starts before the work begins. A few consistent practices make the difference between a smooth project and a frustrating one.
Get at least two or three quotes. A single quote gives you no basis for comparison. Two or three quotes reveal the market rate for the work, expose scope differences between bidders, and let you assess contractor communication quality before any commitment is made. The lowest bid is not automatically the best value if the scope is thin or the materials are underspecified.
Ask for licenses and insurance before work starts. Verify current general liability insurance and, for any work involving workers on your property, workers compensation coverage. Licensing requirements vary by state and trade; confirm the specific requirements in your jurisdiction. A licensed contractor who carries appropriate insurance protects both parties if something goes wrong during the project.
Get the scope in writing. A written proposal that specifies materials, labor scope, timeline, what is included (permits, cleanup, disposal), and warranty terms is the foundation of a professional engagement. Verbal agreements on any of these points invite misunderstanding. For any project over $500, written scope is non-negotiable.
Clarify the payment schedule upfront. A reasonable payment schedule ties major payments to project milestones: a deposit at signing, a payment at material delivery or project start, and a final payment at completion after a walkthrough confirms satisfaction. A contractor who requires full payment upfront before work begins is a red flag in any trade.
Making a Confident Decision
The information in this article is designed to help you ask better questions of the professionals you work with, evaluate their answers with more confidence, and understand the decisions involved in this type of home services project. It is not a substitute for professional assessment of your specific home.
Every home is different. Roof slopes, local weather, tree exposure, soil conditions, and existing system condition all affect what the right solution is for your specific situation. The general principles here apply broadly, but a professional who assesses your home in person will give you guidance that accounts for the details that general articles cannot.
When you are ready to move forward, getting at least two or three quotes from licensed, insured, local contractors is the most important practical step. It lets you compare approaches, assess contractor quality, and confirm that the solution proposed matches your specific situation and budget.
Frequently Asked Questions
Check the controller first: is it powered, is the program set to Run (not Off or Rain Delay)? Try manually activating the zone valve (turn the solenoid screw counterclockwise 1/4 turn to manually bleed the valve). If the zone runs manually but not from the controller: a wiring or solenoid problem. If it does not run manually: a valve problem (diaphragm, solenoid, or debris clog).
Most likely causes: a clogged nozzle (remove, clean under running water, reinstall), a head body cracked from physical impact (replace the head body), or a head that is tilted and cannot pop up fully (straighten and reset). If all heads in the zone are not working: a zone valve problem rather than a head problem.
A brown area after irrigation: indicates a coverage gap. Walk the zone while it runs: look for a head that is not spraying the brown area, a head tilted toward the brown area rather than covering it, or a head that is not reaching the gap (inadequate throw radius for the spacing). Adjust or add a head to eliminate the gap.
A partially closed zone valve (the solenoid is not fully opening the valve). A clogged filter screen at the valve inlet. A leak in the lateral pipe (a broken pipe or a failed head allows water to escape before reaching the other heads, dropping pressure). A blockage in the pipe (rare, but tree root intrusion into older metal pipe can restrict flow). Test: if pressure is low in all zones, the problem is upstream of the zone valves (main supply valve or service pressure).
A head spraying sideways has either lost its nozzle (the stream goes in all directions from the top of the body) or the arc adjustment has been disturbed (the head sprays only part of its intended pattern). For a lost nozzle: the nozzle must be retrieved or replaced. For arc adjustment: most rotor heads have a small adjustment slot on top of the nozzle -- use the adjustment key (usually included with the head) to set the arc to the correct angle.