How to Improve Water Pressure in a Sprinkler System

A typical sprinkler system distributes water throughout a yard or field with strategically placed heads and rotors. But what happens when the water pressure is too low? The grass nearest the sprinkler heads may get overwatered while the grass further out turns brown.

If it seems like your sprinklers aren’t effectively watering where they should be, there could be a few different causes. In a previous post, we’ve laid out how our team diagnoses the cause of low water pressure in a sprinkler system. In this post, we’ll discuss how Andy’s Sprinkler, Drainage, & Lighting addresses those problems in order to get your sprinkler system running effectively again.

Step-by-Step Troubleshooting Overview

Before diving into solutions, here’s a quick DIY-friendly framework to diagnose low pressure:

1. Check if household water pressure is also affected.

2. Test system water pressure with a gauge.

3. Inspect and clean sprinkler heads.

4. Check valves and pressure regulators.

5. Look for leaks in water lines.

6. Consider upgrades like splitting zones, booster pumps, or upsizing lines.

House or Sprinklers…or Both?

The very first step with any water pressure issue is to pay attention to the water in the house, as well as the sprinkler system. If the water pressure in the house has changed, it is highly likely that the main line valve or pressure regulator (both are the very first components found where the city water line meets your primary house water line) is the issue. This would be the job of a plumber.

If the house water pressure hasn’t changed, then the next step is to call Andy’s to take a look at your system!

Other Possible Causes of Low Sprinkler Pressure

• Competing household water demand during peak usage times
  • Temporary municipal supply drops due to construction or hydrant use
  • Restrictions caused by water softeners or filtration systems
  • Undersized pipes or mains that can’t support demand
  • Elevation changes in the yard reducing pressure at higher points

Clean and Adjust Sprinkler Heads

The very first step in diagnosing an improperly functioning sprinkler system is to check for clogged or misaligned sprinkler heads. This is generally more common if only some of the heads have low pressure, but it is possible to have a full set of clogged sprinkler heads.

It is very common for spray heads to get clogged, and even a few grains of dirt can affect spray pattern. Also common is damage from mowers and trimmers, pets and outdoor animals, and human interaction. It is also common to see heads that are no longer spraying the area intended, instead they may be watering a sidewalk or driveway, or away from the intended spray area.

If you suspect that your sprinkler heads need to be cleaned and adjusted, it’s always best to have a professional sprinkler technician address the issue. Sprinkler head nozzles are surprisingly small and delicate given the job they have to perform, and oftentimes we will find that they are the wrong type of nozzle to begin with. This step of system maintenance is recommended at least twice a year, and is included in every Service Call from Andy’s Sprinkler, Drainage, & Lighting.

Beyond Cleaning: Additional Solutions

• Adjust or replace pressure regulators to ensure consistent PSI
  • Install a booster pump for low city supply pressure
  • Reduce the number of sprinkler heads per zone or split overloaded zones
  • Upsize main or lateral lines for better flow
  • Switch to low-pressure sprinkler heads like MP Rotators
  • Use drip irrigation for flower beds and gardens to reduce system demand

Check the Valves

If your sprinkler water pressure has been low for a while, it’s possible that the culprit is a faulty valve. Think of a sprinkler valve like a sink faucet; if you only turn the knob a little bit, the pressure will be low. If you turn the knob all the way, the pressure will be much higher.

There are three types of valves found in all sprinkler systems:
• Main line water valve (the first valve from the city water to your primary house line)
• Backflow prevention valve (separates the house’s primary line from the sprinkler system)
• Zone valves (these control each zone of your sprinkler system)

One of our first steps in diagnosing pressure issues in your system will be to check each of these valves. There could be a wiring issue to the zone valves, or faulty components on any of the 3 valves mentioned above. If valve operation checks out, but the system pressure is still an issue, we will then move on to examining the water lines themselves.

How to Test Your Water Pressure

• Attach a pressure gauge to an outdoor spigot or hose bib
  • Spray heads typically require 20–30 PSI; rotors work best at 30–60 PSI
  • Compare your reading to a neighbor’s water pressure to spot municipal supply issues

Repair Broken or Obstructed Water Lines

Cracked and broken pipes will leak water, which significantly reduces the “charge” (ie: water pressure) in the lines. Sometimes a line leak can easily be identified without digging, which will typically present itself as standing water in an otherwise dry yard or an isolated dead spot in the grass. Other times, finding the leak is much more difficult.

Preventive Maintenance to Keep Pressure Strong

• Schedule seasonal inspections for leaks and damaged pipes
  • Clean sprinkler heads regularly to prevent clogs
  • Flush irrigation lines at least once a year
  • Avoid watering during peak municipal demand hours
  • Winterize your system to prevent cracked pipes
  • Replace aging seals, diaphragms, and valve bodies before failure

If you’re having issues with water pressure in your sprinkler system, contact Andy’s Sprinkler, Drainage, & Lighting today. Our team can diagnose the source of the issue and get your sprinklers back up in running order. Contact us to schedule an appointment with one of our licensed and professionally trained technicians today!

DIY vs Professional Guidance

• DIY-friendly tasks: cleaning or adjusting heads, checking valves, running a pressure test with a gauge
  • Call a professional: repeated low-pressure issues, underground leaks, regulator adjustments, or line resizing
  • Ballpark costs: average irrigation repair runs $200–$300; booster pumps cost $50–$300 depending on size and installation