Irrigation Troubleshooting Guide – Bob Carr
If you’ve ever turned on your irrigation system and noticed that some zones work perfectly… while others don’t come on at all—you’re not alone.
This is one of the most common and frustrating issues homeowners run into.
And the question I hear all the time across Maryland, DC, and Northern Virginia is:
“Bob, why are some of my sprinkler zones not turning on at all?”
It’s confusing because part of the system works.
- The controller turns on
- Some zones run fine
- But others? Nothing happens
No water. No sound. No movement.
After more than 42 years as a home improvement contractor here in the DMV—since 1983—helping thousands of homeowners (with 600+ reviews averaging 4.8 stars and an A+ Better Business Bureau rating), I can tell you this clearly:
👉 When some zones don’t turn on, it’s almost always a specific, localized issue
👉 And once you identify it, the fix is usually straightforward
The key is knowing where to look.
So in this article, I’m going to walk you through this the same way I would if we were standing next to your controller and valve box together:
- What’s actually happening when zones don’t turn on
- The most common causes (and how to identify them)
- What it typically costs to fix each issue
- Real homeowner case studies
- And how to prevent it from happening again
Let’s break it down.
The Big Idea Most Homeowners Miss
Before we dive into causes, you need to understand this:
👉 If some zones work and others don’t, your system is partially functioning
That tells us something important right away:
👉 The controller is likely working
👉 The main water supply is likely working
Which means:
👉 The issue is usually isolated to the specific zones that aren’t turning on
That narrows things down significantly.
What This Problem Usually Looks Like
Here’s how homeowners typically describe it:
- “Zone 1 works, but Zone 2 won’t come on”
- “Half my system runs, half doesn’t”
- “Nothing happens when a specific zone is supposed to run”
- “It worked last year, now some zones are dead”
Each of these gives us clues.
The 10 Most Common Causes (And What They Cost to Fix)
Let’s walk through what we actually find in the field.
1. Faulty Solenoid (Most Common)
The solenoid is the electrical component that opens the valve for each zone.
If it fails:
👉 That zone will not turn on at all
Typical fix: Replace solenoid
Cost: $100 – $300
2. Valve Failure
Each zone has its own valve.
If the valve:
- Is stuck
- Is damaged
- Won’t open
👉 Water never reaches that zone
Typical fix: Repair or replace valve
Cost: $200 – $900
3. Wiring Break or Disconnection
Wires connect your controller to each valve.
If wiring is:
- Cut
- Corroded
- Disconnected
👉 The signal never reaches the valve
Typical fix: Repair wiring
Cost: $150 – $800
4. Controller Terminal Issue
Sometimes the controller itself has a problem at a specific terminal.
👉 That zone won’t activate
Typical fix: Repair or replace controller
Cost: $200 – $1,200
5. Clogged or Damaged Valve Internals
Debris inside a valve can prevent it from opening.
👉 No water flow to the zone
Typical fix: Clean or rebuild valve
Cost: $150 – $500
6. Zone Shutoff Valve Closed
Some systems have manual shutoff valves for specific zones.
👉 If closed, the zone won’t run
Typical fix: Open valve
Cost: $0 – $100
7. Pipe Break in That Zone
If there’s a break:
👉 Water may not reach the heads properly—or may leak underground
Typical fix: Locate and repair pipe
Cost: $300 – $1,500
8. Backflow or Pressure Issue Affecting Specific Zones
Sometimes pressure inconsistencies affect certain zones more than others.
Typical fix: Diagnose and correct pressure
Cost: $300 – $1,200
9. Zone Overload or Design Problem
If a zone has too many heads:
👉 It may not activate properly
Typical fix: Adjust or redesign zone
Cost: $1,000 – $3,500
10. Seasonal Startup Issues
At the beginning of the season:
- Valves may stick
- Air pockets may exist
👉 Zones may not activate correctly
Typical fix: System startup service
Cost: $150 – $400
Real DMV Case Studies
Case #1: “One Zone Was Dead”
Rockville
Problem:
- Single zone not turning on
Cause:
- Bad solenoid
Cost: 👉 $180
Result: 👉 Zone restored same day
Case #2: “Half the Yard Wasn’t Watering”
Northern Virginia
Problem:
- Multiple zones inactive
Cause:
- Wiring damage
Cost: 👉 $650
Result: 👉 System fully restored
Case #3: “We Thought It Was the Controller”
Bethesda
Problem:
- One zone wouldn’t run
Cause:
- Valve failure
Cost: 👉 $550
Result: 👉 Problem solved
Case #4: “It Worked Last Year”
Silver Spring
Problem:
- Zones not activating at startup
Cause:
- Seasonal valve issues
Cost: 👉 $250
Result: 👉 System running normally
Why This Problem Gets Worse Over Time
If ignored:
- Lawn areas dry out
- System imbalance increases
- Additional components fail
👉 One dead zone can lead to bigger issues
What Most Homeowners Get Wrong
Mistake #1: Blaming the Controller Immediately
👉 Often not the issue
Mistake #2: Ignoring a Single Zone
👉 Leads to lawn damage
Mistake #3: Replacing Parts Without Diagnosis
👉 Wastes money
How to Diagnose It Yourself
Before calling a professional:
- Run each zone manually
- Listen for valve activation
- Check for clicking at the controller
- Look for visible water or leaks
- Note which zones are affected
👉 This helps narrow down the issue
The Right Way to Fix It
After 42+ years, here’s how we approach it:
- Test controller output
- Inspect wiring
- Check valves and solenoids
- Identify failure point
- Repair or replace component
👉 That’s how you fix it correctly the first time
Cost Timeline (If You Wait)
Year 1:
- One zone not working ($150 fix)
Year 2–3:
- Lawn damage spreads
Year 4+: 👉 System imbalance and larger repairs
Long-Term Value of Fixing It Right
When addressed properly:
- All zones function correctly
- Lawn stays consistent
- System efficiency improves
Final Thoughts
If some of your sprinkler zones aren’t turning on, remember this:
👉 The system is giving you a clear signal
👉 Something specific isn’t working
After more than four decades helping homeowners throughout the DMV, I can tell you this:
The key isn’t guessing.
👉 It’s identifying the exact cause and fixing it once
Quick Answers
Q: Why are some zones not turning on?
A: Usually solenoid, valve, or wiring issues
Q: What’s the most common cause?
A: Bad solenoid
Q: What does it cost to fix?
A: Typically $100 – $800 per zone
Q: Is this a big issue?
A: It can be if ignored