How To Fix Low Water Pressure in Sprinkler Systems: Troubleshooting Tips

Many people depend on sprinklers to keep their yards healthy and vibrant. If your sprinkler system experiences a loss in water pressure, it can be devastating for your yard. When your sprinkler system has low water pressure, you’ll want to get it fixed quickly to protect your yard, prevent water waste, and avoid increases in your water bill.

In this blog post, HEB Plumbing & Sprinkler will explain what to do if your sprinkler system has low water pressure.

Common Causes of Low Water Pressure in Sprinkler Systems

Low water pressure in a sprinkler system can have several causes. Here, we’ll explore some of the most common ones. Please note this list is not exhaustive.

Blocked or Damaged Sprinkler Heads

A blocked or damaged sprinkler head can reduce water pressure. It can also become dirty, restricting water flow. 

If the cause of low water pressure is trouble with the sprinkler heads, it may be limited to a single section of your yard.

Leaks in the Irrigation System

Leaks in an irrigation system reduce water pressure and can waste water. Some signs of irrigation system leaks are unusually wet areas, discolored lawns, or lawn depressions.

Water Supply Issues, Main Problems, or Low Municipal Pressure

Sometimes, low water pressure is not caused by anything on your property but by low municipal water pressure. This could result from increased watering in the community due to hot, dry weather. If the problem is due to low municipal water pressure, you’ll need to report it to your local water company.

Incorrect Zone Valve Settings

Problems with sprinkler system zone valves can also result in low water pressure. The following are a few ways zone valves can cause low water pressure.

Incorrect Installation – A zone may lack water pressure due to a faulty installation. For example, two connected zones might have been set up to use the same amount of water pressure.

Incorrect Timer Setting – Zone valve timer problems are the biggest reason one sprinkler system zone experiences intermittent low water pressure. This could cause one zone to be behind others, causing a delay in full water pressure reaching that zone.  

Backflow Preventer Valve Malfunction

A common cause of low sprinkler system water pressure is a backflow preventer valve that does not open fully. The backflow preventer has two main pipes, one vertical and one horizontal. Each pipe has a handle that can be turned to run even with the line, which opens the valve, or across the line, which shuts the valve.

If a handle is partially turned (or only one is turned), it is enough to restrict water flow, resulting in low water pressure.

Pipes Are Too Small

If the pipes leading to the sprinkler system are too small, they can restrict your sprinkler system’s water pressure.

Troubleshooting and Diagnosing Low Water Pressure

While it is best to leave lawn sprinkler repairs to professionals, if you have the knowledge and tools, you may be able to diagnose your low water pressure and do some repairs yourself. If you are unsure about anything, please do not hesitate to contact a sprinkler plumbing professional.

The following are a few methods of sprinkler system troubleshooting.

Caution: When working with your sprinkler system, be sure to wear appropriate work gloves at all times.

How To Check Sprinkler Heads for Blockages or Damage

Dirt buildup on sprinkler heads is a common cause of blockages. Check the sprinkler head for dirt. Inspect the sprinkler head’s nozzle and screen if you don’t see dirt buildup on the sprinkler head.

Look for signs of damage to your sprinkler head, such as dents, cracks, obstructions, and broken pieces.

Determining if a Leak Is Inside or Outside of a Home

First, you’ll want to determine the source of your leak. If you’ve confirmed it’s not an indoor leak, you can work to find the leak in your sprinkler system.

Step 1. Find the home’s water shutoff valve. It is generally located in a basement, garage, or outside wall. 

Step 2. Shut off the valve to turn off your home’s water supply.

Step 3. Return to your water meter. If the leak indicator is no longer moving, the leak is in your home. If it keeps moving, the leak is outside, between the home and the meter.

Inspecting the System for Leaks

There are several ways to check your sprinkler system for leaks. You can locate them by taking the following steps.

Inspect sprinkler valves and check the sprinkler stations to find leaks causing low water pressure.

Inspecting the Sprinkler Valves: Ensure the valve boxes are dry and not flooded.

Inspecting the Sprinkler Stations: If your sprinkler system is spread out, you’ll need a second person to help you examine the sprinkler stations.

The following are signs of leaks the spotter will need to watch out for:

• The sprinkler’s base is flooding. This could be due to malfunctioning valves that don’t shut off correctly.
• If you see water geysers or sprays, it could be due to missing sprinkler heads. 
• If water is spraying out between sprinkler heads, it may be due to a cracked lateral line.
• Water gathering in the grass between sprinkler heads typically means a steady underground pipe leak.
• If water is spurting from a sprinkler’s base, it could be caused by a broken seal where the nozzle or riser connects to the underground water supply.

Testing Water Pressure With a Gauge

Different types of sprinkler emitters have different PSI requirement ranges. The following is a general range of PSI requirements for the three main types of emitters. Please note that PSI requirements may vary based on particular emitter models—check with the manufacturer for an accurate PSI range.

Spray Heads: 20 to 40 PSI

Rotary Heads: 30 to 90 PSI

Drip Emitters: 15 to 40 PSI

You’ll need a specific tool depending on where you measure the water pressure and the type of sprinkler head you have. You can use the following tools to test water pressure: 

• Pitot tube for taking pressure readings at a rotary nozzle
• Hose bib adapter for measuring pressure at a hose bib
• Pressure gauge adapter tee to measure spray body nozzle pressure
• Measuring wheel to measure the space between sprinklers
• Irrigation multi-tool for making quick repairs or adjustments

Using a pressure gauge, you can measure the water pressure at the sprinkler head.

Step 1. Shut off all plumbing fixtures inside and outside the house, such as hoses, sinks, and showers.

Step 2. Connect the pressure gauge to the pitot tube or the adapter tee and gauge to the spray head.

Step 3. Activate a single sprinkler zone (ideally the farthest or most elevated area from the water source or problem area).

Step 4. Go to the zone you wish to test, and wait for the sprinkler head to pop out and begin spraying water. Please note that you will get wet during this step.

Assessing the Water Supply Line 

Your sprinkler system depends on the main water supply line for water. If this line is damaged, it can affect the water pressure in your sprinkler system.

You can conduct the following test to see if the water supply line is leaking.

Step 1. Turn off all faucets and ensure that no water is being used inside or outside the home.

Step 2. Locate your water meter (it tends to be in a box in front of your home by the sidewalk or street).

Step 3. Check the water meter. If your water meter is analog, look for a small silver wheel or red triangle dial. If either is moving, that indicates a leak. If the water meter is digital, shine a flashlight on the gauge and see if the number flashes above zero. If it does, that indicates a leak.

Measure Sprinkler Spacing

Your sprinkler system manufacturer should have a recommended sprinkler head spacing. When you find it, you can measure your sprinkler head distance, preferably using a measuring wheel.

Solutions for Fixing Low Water Pressure

You can address low water pressure in your sprinkler system in several ways. While you may be able to do some of these fixes yourself, it’s a good idea to hire a professional.

Install a Home Filtration System Bypass

Home filtration systems are common nowadays. However, they often reduce water supply pressure and flow. The best way to resolve this issue is to connect your sprinkler system plumbing to your water source before it reaches the home filtration system. As your sprinkler system generally doesn’t require filtering, it may increase your available water pressure. Given its complexity, hiring a professional to install a home filtration bypass system is recommended.

Clean or Replace Sprinkler Heads and Bodies

You can clean dirty sprinkler heads; however, if sprinkler heads and bodies are damaged, they may need to be replaced. Make sure the sprinkler system is off before you clean or work on it.

Cleaning Sprinkler Heads 

To conduct a routine cleaning of your sprinkler head, you’ll need the following tools:

• Needle-nose pliers
• Adjustable vice grip
• Soft-bristle brush or towel

You should clean your sprinkler head filters twice a year.

Step 1. Lift the sprinkler head out of the ground.

Carefully lift the sprinkler head tip or sleeve. The sprinkler head nozzle should come up as if it were turned on. You may need to use a pair of adjustable vice grips to ensure the shaft stays in place when you clean it.

Step 2. Take the filter out.

To access the filter, unscrew the top of the sprinkler head or nozzle. The filter is small and located in the shaft housing, just under the nozzle head. Needle-nose pliers may be required to remove the filter.

Step 3. Clean the filter.

Take a soft-bristle brush or a clean towel and wipe off the debris from the filter. Sediment, dirt, and grass tend to accumulate there.

Step 4. Put the filter back and flush the system out.

If you have adjustable vice grips holding the shaft in place, keep them on. Once the filter is clean, place it back in the sprinkler shaft and put the nozzle head back on. You can then remove the vice grips.

Activate the sprinkler system for a few moments so all the water can run out—this helps remove any remaining obstructions.

Deep Cleaning Sprinkler Heads

If the sprinkler system is still clogged after cleaning the filter, you can try deep cleaning it. This is also a good idea if the sprinkler heads haven’t been cleaned recently. Cleaning only the filter may not be enough to remove mineral buildup.

You’ll want to deep-clean your sprinkler heads at least annually, every other year, or more often if you experience frequent clogs.

To deep clean sprinkler heads, you’ll need the following tools:

• Needle-nose pliers 
• Adjustable vice grip
• Cleaning solution (vinegar or rust remover)
• Soft-bristle brush or towel

Step 1. Take off the sprinkler head.

Remove the sprinkler head to begin deep cleaning it—the same way you would when cleaning the filter. Most sprinkler heads can be removed by twisting them off the sprinkler line. Raise the tip or sleeve of the sprinkler nozzle. Then, unscrew the sprinkler head and carefully remove it.

Step 2. Wipe off the sprinkler head.

Take a soft-bristle brush or a cleaning towel and wipe the sprinkler head, removing any debris.

Step 3. Soak the sprinkler head.

Put the sprinkler head in a bucket large enough to submerge it fully. Then, either soak it in a half-and-half mixture of vinegar and water or cover it with a rust remover (available at local hardware stores). Next, wait for 30 minutes. Caution: Be sure to follow the instructions for the rust remover, as it can be dangerous.

Step 4. Brush and rinse the sprinkler head.

Brush the sprinkler head one last time to remove any remaining buildup. Then, rinse it in cool water and reattach it to the housing.

Step 5. Run the system.

When the sprinkler head is back on the line, run your sprinkler system to flush any remaining debris.  

Repairing Leaks in the System

Repairing water leaks can help conserve water and improve the water pressure in your sprinkler system. While you may be able to fix some leaks yourself, others should be left to professionals.

Warning: Before digging in your yard, contact your utility company.

Repairing a Leaking Sprinkler Valve

Caution: Working with electricity can be dangerous and even lethal. If you don’t know how to do something safely, reach out to a professional.

Step 1. Shut off the power at the breaker. This is crucial for safety.

Step 2. Turn off the water supply. Turn off the water supply to the sprinkler system to prevent excess water from escaping.

Step 3. Access your valve box. Locate the valve box and remove the lid to access its internal components.

Step 4. Clean out the area. Take a garden towel to remove debris and mud from the valve box.

Step 5. Absorb moisture from the valve box. Put dry rags in the valve box to absorb water for a clean workspace.

Step 6. Remove the solenoid. Gently twist the low-voltage solenoid, carefully remove it, and set it aside.

Step 7. Drain water from the system. Let any remaining water drain out of the system by gravity.

Step 8. Gain access to internal parts. Take a Phillips-head screwdriver and unscrew the valve bonnet to access the internal parts.

Step 9. Take out parts. Carefully and gently remove the spring and diaphragm gasket from under the bonnet.

Step 10. Check for damage. The diaphragm gasket is a common place for leaks, so inspect it for damage.

Step 11. Install the new diaphragm. Line up the holes of the new diaphragm with the valve body.

Step 12. Replace and secure the components. Put the spring back into position over the diaphragm. Then, put the valve bonnet back on, taking care to tighten the screws in a crisscross pattern.

Step 13. Reattach the solenoid. Reconnect the solenoid valve, ensuring the connections are stable.

Step 14. Secure the electrical wiring. Use waterproof wire connectors to help reduce corrosion.

Step 15. Restore the work area. Remove the rags from earlier, and put gravel or clean stone in their place to help prevent silt buildup.

Step 16. Turn the power back on at the breaker. You can turn the power back on for the solenoid at the breaker.

Step 17. Turn on the water supply. At this point, you can turn the water back on for the sprinkler system.

Replacing Part of a Supply Line Hose

To repair a flexible hose section, you’ll need one of the following tools:

• Tubing cutter
• Tin snips
• Pipe cutter

Dig cautiously in the area of the suspected supply line hose. Do not force the shovel into the ground, which could break the hose.

Once you’ve located the underground supply line, dig 12 inches horizontally on either side. Then, uncover the broken section and about six inches on each side of it. 

Replacing a Flexible Hose Section

Step 1. Measure and make a guideline of around two inches on each side of the leaking section. Then, use a tubing cutter, tin snips, or a pipe cutter to cut the hose to remove the cracked part.

Step 2. Using the removed piece as a guide, cut a new flexible hose section the same length as the previous one.

Step 3. Attach compressor couplings to both ends of the new flexible hose section. Slide each coupling about one or two inches onto the hose to help prevent it from slipping or moving. If necessary, wet each end of the new hose section to make fitting the couplings easier.

Step 4. Push the other side of the two couplings onto the buried flexible hose until the connection becomes tight.

Step 5. Turn the water on again to check for any leaks.

Repairing or Replacing a PVC Supply Line Section

Depending on the damage to a PVC supply line, it will have to be either repaired or replaced.

• If the leak is minor, you can seal the leaking section with epoxy, rubber repair tape, or silicone.
• If the leak is major, remove the damaged piece and splice a telescopic slip covering in.

Replacing a Flex Line

If there is damage to a flex line in your sprinkler system, it will need to be replaced.

Step 1. Dig up the soil between the sprinkler head and fitting, or turn off the section where the main supply line connects to the flex line. Then, unscrew the sprinkler head counterclockwise.

Step 2. Get the new 12-inch flex hose and wrap the large one-inch end securely using two to three layers of Teflon tape. Screw the flex hose clockwise into the shutoff valve or PVC fitting until it becomes snug. Then, tighten it until it is wrench-tight.

Step 3. Turn on the water again to flush debris or dirt from the flex hose. Let it run for a minute or so, then turn it off.

Step 4. Thread the sprinkler head to the flex hose’s small end until it is firm. You don’t need to tighten it with a wrench or use any Teflon tape.

Step 5. Check for leaks by turning back on the water.

Adjusting Zone Valves for Optimal Pressure

Zone valves that are not open enough could be restricting water pressure in sections of your yard.

Ensure the Main Water Valve and Shut-Off Valves Are Fully Open

Sprinkler systems generally have a shut-off valve. You’ll want to ensure the shut-off valve is completely open to get the necessary amount of water pressure for your sprinkler system. The main water valve that provides water to your home will also need to be fully open.

Add a Booster Pump

If areas of your sprinkler system constantly have low water pressure, a booster pump may help. Booster pumps can increase the flow rate and pressure of your water. Consult with a professional to find the right pump size for your situation.

Contact a Plumbing Professional Serving Belford and Surrounding Areas

If you are having trouble fixing the low water pressure in your irrigation system or are unsure how to proceed, reach out to a plumbing professional to save yourself time and hassle. At HEB Plumbing, we have extensive experience handling sprinkler systems and are ready to help you resolve your sprinkler system issues. 

Preventive Measures To Maintain Optimal Water Pressure

Regular preventive maintenance can help prevent low water pressure issues, potentially saving money and avoiding inconveniences. While there is no guarantee that low water pressure will never occur, you can reduce the chances of it happening. 

The following are a few steps to help maintain an optimal level of water pressure in your sprinkler system.

Inspect the System Regularly

Seasonal Checks: Inspect the system at the beginning and end of each watering season.

Look for Wear and Tear: Check valves, pipes, and sprinkler heads for signs of wear.

Add Upgrades to the Sprinkler System

Upgrade Components: If needed, consider upgrading to newer and more efficient sprinkler system components. Some sprinkler heads are designed to work well with low water pressure.

Add Smart Controls: Adding smart controls to your sprinkler system can help you monitor it and improve its efficiency.

Flush the Sprinkler System and Maintain the Filters

Routine System Flushing: Flush your sprinkler system out periodically to clear debris.

Check Filters: Make sure any filters in the sprinkler system are clean and working correctly.

Contact HEB Plumbing for the Best Plumber in Bedford and Surrounding Areas

Without adequate water pressure in your sprinkler system, your lawn may lack the irrigation it needs to look its best. By identifying sprinkler system issues and being proactive with maintenance and repairs, you can help your lawn get even coverage and reduce water waste. If you are unsure about anything, please contact us or a qualified plumber in your area. 

Since 1980, HEB Plumbing & Sprinkler has been helping customers in Bedford, Texas, and the surrounding areas, and we have received many five-star reviews for our work. Whether you have low water pressure in your sprinkler system or another issue, our experts can help. Contact us today and get your sprinkler system working as it should!

Additional Resources

• What to Know About Your Arlington, Texas Sprinkler System
• How Does a Sprinkler System Work
• What is the Best Time of Day to Water my Grass