When your sprinkler system starts acting lazy — weak spray, heads not popping up, zones not reaching the corners — low pressure is often the culprit.
At TLC, we see it all the time in Maryland yards. And while pressure loss is frustrating, the good news is it usually traces back to a handful of common causes.
Let’s dig into the seven most likely reasons your irrigation system is losing pressure — and what to do about each one. We’ll break each down with symptoms, causes, fixes, and what you can do as a homeowner.
1. Clogged Sprinkler Heads
Clogs are the most common pressure problem we see — and the easiest to fix.
What Happens: Sprinkler heads sit at ground level and deal with all kinds of yard debris. Grass clippings, mulch, dirt, and even bugs can clog the nozzle or internal filter.
Symptoms: – One or more sprinkler heads sputter or don’t spray far – Water output looks misty or thin – Coverage looks uneven compared to last season
How to Fix It: – Turn off the water – Unscrew the nozzle – Rinse both the nozzle and screen filter – Use a paperclip or nozzle-cleaning tool for stuck debris – Replace cracked or worn heads
Prevention: – Inspect and clean heads once a month during the watering season – Avoid mulching too close to heads
Bob’s Tip: If you mow your own lawn, give heads a once-over each week — especially after a big cut.
2. Broken Pipes Underground
A pipe leak doesn’t always gush water above ground. Often, the pressure drop is your only clue.
What Causes It: – Tree root intrusion – Soil movement after heavy rain or winter frost – Accidentally hitting lines while digging or aerating
Symptoms: – A patch of lawn stays soggy even when the system is off – Water bubbles from underground during a cycle – A zone doesn’t fully activate or sprays weakly
Fixing It: – Shut off your system – Call TLC — we use electronic leak detection and pressure testing to pinpoint the issue – Once located, we dig safely, repair or replace the line, and test again
Prevention: – Avoid DIY digging near irrigation lines – Schedule yearly inspections, especially if your system is over 10 years old
TLC Tip: We’ve repaired broken lines for as little as $100 when caught early. Left alone, those same leaks can rot roots and damage your landscape.
3. Zone Valve Problems
Every irrigation zone is powered by a valve. If it’s partially open, stuck, or worn out, it throttles water flow.
What Causes Valve Issues: – Worn solenoids (electronic switch inside the valve) – Debris inside the valve – Improper installation or wiring issues
Symptoms: – One zone is consistently underperforming – Sprinkler heads work for a second, then go limp – You hear clicking but nothing activates
DIY Check: – Open the valve box and inspect the suspect zone – Look for loose wires or debris – Try manually opening the valve
Professional Fix: – Replace the solenoid or entire valve assembly – Re-wire connections and test flow
Bob Says: Valves are like traffic cops for your water. If they’re not working right, everything slows down.
4. Backflow Preventer Issues
Your backflow device keeps dirty irrigation water from mixing with your home’s drinking water. It’s vital — and it also regulates water pressure.
Types of Backflow Devices: – Pressure Vacuum Breaker (PVB) – Reduced Pressure Zone (RPZ) – Double Check Valve Assembly
What Goes Wrong: – Internal springs wear out – Debris blocks the valve – Cold snaps crack plastic parts
Symptoms: – Visible leaks around the device – Strange whistling or hissing during operation – Low pressure across all zones
Fix: – Inspect for cracks or leaks – Have a certified technician repair or replace the assembly – Annual backflow testing is required in most counties
TLC Note: If your backflow preventer hasn’t been serviced in a few years, it could be the pressure problem you’ve been chasing.
5. Low Municipal Water Pressure
Sometimes it’s not your system — it’s the city water supply.
What Causes It: – Seasonal demand spikes (summer irrigation, hydrant testing) – Aging infrastructure or main line issues – Local construction or flushing events
How to Check: – Attach a pressure gauge to your outdoor spigot – Normal pressure is 40–60 psi; below 35 psi is considered low
Fixes: – Install a booster pump to maintain flow – Add a pressure-regulated zone system – Consider a rainwater harvesting or cistern system for backup
Case in Point: We installed a booster pump in a Columbia home that had a 15 psi city supply. It now runs 6 zones beautifully, even during peak watering hours.
6. Overloaded Zones
Adding heads without recalculating flow is like plugging too many appliances into one outlet.
Common Mistakes: – Adding heads for new plants without rebalancing GPM – Running too many rotor heads in a single zone
What You’ll See: – Some heads barely move or pop up – Water coverage is inconsistent across the zone
Solutions: – TLC will audit your zone design – We may split a zone into two – Upgrade to high-efficiency nozzles that use less water
Prevention: – Always have a pro add heads or modify coverage — we calculate exact water usage before making changes
Bob’s Tip: It’s not about how many heads you can fit. It’s about how many you should.
7. Clogged Filters or Pressure Regulators
Filters and regulators keep your system balanced — until they clog up with sediment, sand, or mineral scale.
Where They’re Found: – At the main line before zones – Inside valve boxes (inline filters) – On drip systems or micro-irrigation zones
Symptoms: – All zones lose pressure equally – You have hard water or are on a well
How to Fix: – Locate and clean filters with clear water and soft brush – Soak in vinegar for mineral removal – Replace regulators showing corrosion or damage
When to Replace: – Every 3–5 years depending on water quality
TLC Note: We include filter checks in all our mid-season and winterization visits.
Bonus: Other Silent Pressure Killers
Sometimes the issue isn’t obvious. These can also impact pressure:
- Crimped or kinked hoses
- Incorrectly set controller run times (causing pressure overlap)
- Partially closed shut-off valves (on the water supply)
If you’ve checked the usual suspects and nothing stands out, call TLC. We’ve seen it all.
When It’s Time to Call TLC
DIY is great — until it’s not. Here’s when it pays to bring in a pro:
- You’ve tried basic cleaning and still have poor pressure
- Water bills are high, but your lawn is still dry
- Zones are performing unevenly
- You’re planning to expand your landscaping
We bring pressure gauges, flow meters, underground leak detectors, and over 30 years of Maryland lawn know-how.
We don’t just fix problems — we find out why they happened.
Final Thoughts: Don’t Let Pressure Problems Linger
Pressure issues are easy to ignore for a while. But they come at a cost: – Water waste – Plant stress – Higher bills – Potential damage to your system
Regular maintenance, prompt repairs, and smart system design make all the difference. At TLC, we treat every system like our own — and we always take time to explain what we’re doing and why.
Need help troubleshooting? Want an honest second opinion? Schedule a pressure test with TLC, and let’s get your system running like new again.
Green lawns grow with good pressure — and great care.