Diagnosing Sprinkler Valve Leaks: 8 Causes and Their Fixes

As an Amazon Associate we earn from qualifying purchases made on our website. If you make a purchase through links from this website, we may get a small share of the sale from Amazon and other similar affiliate programs.

Did you know that landscape irrigation systems account for about 30% of water usage in the United States? This means that any leakage from these systems leads to so much wasted water. That said, sprinklers are one of the most expensive systems to maintain, and when they start leaking, it can cause other major problems.

The common causes of sprinkler valve leaks include broken O-rings, excess pressure, start-up or shut-down problems, damaged valves, blocked distribution lines, and damaged sprinkler heads. To solve these, replace the O-rings, use cycling valves, seal pipe joints, remove clogs, and use new valves.

The rest of this blog post will discuss these eight causes of sprinkler leaks and how to fix them by replacing the O-rings, using cycling valves, sealing pipe joints, removing clogs, and adding new valves. Read on for insights into the tips that can help save you money on your water bills, as well as prevent any costly repairs down the road.

1. Broken O-Rings or Seals

This is one of the most common causes of sprinkler leaks.

The good news? This type of leak can easily be fixed with a simple O-ring replacement from your local hardware store.

The bad news? This leak could potentially lead to more costly repairs or even flooding if not repaired quickly enough.

How To Fix

To fix broken 0-rings or seals, follow the steps below:

  1. Remove the old seal and replace it with a new one.
  2. Reconnect any other parts that were disconnected during installation or repair.
  3. Make sure everything lines up correctly and that there are no gaps for the seals to keep water out. In many cases, just tightening screws may be all that’s needed as well.

2. Too Much Pressure on the Sprinkler System

When you have too much pressure on the sprinkler system, it can lead to a leak. This is often caused by too many heads per zone or an oversized pump running all day long.

How To Fix

The first thing you’ll want to do is reduce the number of fixtures in each irrigation zone and make sure your pump doesn’t run more than 12 hours at a time without being shut off for maintenance purposes. 

It would help if you also considered installing automatic cycling valves so pumps don’t cycle unnecessarily during certain times of the year when they’re not needed as frequently.

If you’re unfamiliar with them, these devices automatically turn the water on and off based on soil moisture sensors hidden below the ground. 

Alternatively, if the valves are leaking due to an excessive amount of water being used, you can install a flow control valve that’ll limit the amount of water coming out and prevent damage from occurring.

In that regard, I recommend this Toro Underground Sprinkler System (available on Amazon.com). Besides ensuring smooth water flow, it comes with a backflow preventer and works perfectly with any irrigation system, making it the ideal option if you need a versatile valve.

In addition, you should also have professionals come out at least once per season to do a thorough inspection so any problems can be addressed before they become severe. This will save you time in the long run–and money too!

3. Start-Up or Shut-Down Problems

If you have start-up or shut-down problems with your sprinkler system, this could lead to leaks. This usually happens when the pump doesn’t get enough water due to a blockage in pipes, insufficient pressure on the lines, and dirty filters or pump screens.

How To Fix

To fix start-up and shut-down problems, ensure that all pipe joints are properly sealed, and no cracks are present before troubleshooting any other potential leakage causes. You can also use an air release valve for sprinklers if there’s too much pressure just before start-up time.

There may also be such valves inside irrigation zones as well–check those also.

The best thing to do is contact a professional plumber or irrigation specialist for help if you’re unsure what needs to be done.

4. Broken or Damaged Valves

If you have a broken sprinkler valve, this can cause leaks. This is also true if the valves are working correctly but there’s some other problem with your system that has led to water pressure loss and makes it difficult for them to work as intended.

How To Fix

If the only thing wrong is a faulty sprinkler valve, all you need to do is replace it. To replace a faulty valve, follow these steps:

  1. Shut off the water supply.
  2. Shut down the power to your irrigation system (if you have electric sprinklers, make sure they’re turned off as well). This will help avoid damage.
  3. Remove the sprinkler valve from your system. If it’s stuck, use a pipe wrench or pliers to remove it (don’t force anything if you’re concerned about breaking any parts). If there’s significant corrosion, it may be wise to replace the entire pipe instead of just the valve. If you’re not sure whether or not to do this, consult a professional plumber/irrigation specialist for advice before proceeding.
  4. Once removed, unscrew and remove any debris that’s inside your sprinkler system. The pipes should now appear clean.
  5. Install a new sprinkler valve and make sure that all connections are sealed properly
  6. Reattach the power to your irrigation system (if you have electric sprinklers, turn them back on). Make sure everything is working correctly by testing it out.

Here’s a YouTube video describing how to replace old sprinkler valves:

Tip: Remember–there may be bigger problems behind any of these smaller ones, so don’t forget to troubleshoot the whole system before assuming everything is okay just because one small part was replaced.

An irrigation specialist will often know what else needs checking for water pressure on each zone/head area (or lack thereof) to be at a safe level.

However, if you know the valve is broken but don’t want to pay someone else for service, replacing it yourself will work just as well. Nonetheless, this can get tricky depending on where the sprinkler valves are located–so do your research first and make sure you have all of the tools needed before attempting any repairs (i.e., wrenches, pliers).

5. Blocked Distribution Lines

If you’re noticing leaks in your system, it could be because of a blocked distribution line. This blockage can be caused by dirt, rust or other debris that the water can’t flow through. Another thing to keep in mind is that your system may be too close to a tree or other vegetation, either of which could be the culprit.

How To Fix

If there’s an obstruction at one sprinkler head that prevents water flow, this can cause valves downstream to leak as well. Therefore, if you have any suspicions that this is happening with your system, start by cleaning out those heads.

To do so, remove them from their fittings using pliers and carefully clean off all dirt and debris before reattaching them securely again.

6. Malfunctioning Sprinkler Heads

If you have a malfunctioning sprinkler head, this could cause leaks. This is especially true if the heads aren’t being cleaned monthly (as instructed) and buildup on the ports prevents them from opening to release water pressure or close properly.

How To Fix

If your problem is due to dirty ports/spray nozzles, use an old toothbrush wrapped tightly with wire nuts around it for increased grip while scrubbing off any debris. You can then reattach each head securely before turning your system on again.

Caveat: If your problem is due to valves not opening or closing correctly (as would be seen if there were leaks because of low water pressure), replacing them yourself may also work. 

However, this can get difficult depending on where the sprinkler heads are located. Because of that, it would help to do your research first and make sure you have all of the tools needed before attempting any repairs (i.e., wrenches, pliers).

7. Poorly Maintained Sprinkler System

If your sprinkler system isn’t being maintained, this could lead to leaks. This can happen due to the age of your equipment and a pressure loss in pipes that’s making it difficult for valves to work as intended or because there may be some other problem with your entire system, such as broken wires/sprinklers.

How To Fix

The best way to fix this problem is by hiring an irrigation specialist or plumber to inspect your system and make the necessary repairs. However, if you’re pressed for time and money, it’s best to determine whether this is a job that can be done by yourself.

If so, use your wrenches/pliers for tightening any loose connections where needed. For example, you could use wire nuts (or connectors) to reattach the wires together securely after cutting them free of their opening at either end. Then apply some heat shrink tubing over each cut-end afterward to protect it from water damage during operation.

You can also use a plunger to unblock the sprinkler head if it’s not opening or closing properly. Simply submerge it in water, attach the flexible rubber end of your plunger securely over the top, and then work at “plunging” until you feel resistance/vibration from dislodging any obstruction inside.

8. Poorly Drilled Pipe

If you have poorly drilled pipes and there are leaks at the sprinkler head, this is a common cause for concern. If your whole system has poor water pressure/flow as well, then it’s likely due to some other problem with pipes and valves, but if only one or two heads are leaking, chances are this is the cause.

How To Fix

This can often be fixed by securely re-drilling the holes into which they’re threaded before retightening them again (i.e., using pliers). But note that if this doesn’t work, then replacing damaged pipe washers may also help.

To do so, simply use wrenches to twist off any fittings where needed while making sure that you don’t give them a hard tug. This can knock the pipes loose after they’ve been tightened securely on already.

If this isn’t enough to fix it, make sure all pipe connections are secure. Try again before calling in a professional to inspect your system (which will likely require digging).

Finally, if none of these things works, then your best bet would be replacing sprinklers/nozzles or even entire heads. Note that while you could do this yourself with some practice, it’s often easier for a plumber or irrigation specialist to install new parts due to their expertise.

How To Maintain Sprinkler Systems for a Longer Life Span

The most important thing you can do to keep your sprinkler system running for months without leaking or malfunctioning is regularly maintaining and inspecting it.

In this regard, here are some crucial tips to keep your sprinkler system functioning without disruptions.

Check for Leaks and Clogs

Ensure you check for leaks or clogs (such as leaves) at least once every two weeks. If possible, check for these issues even more often. This will help you detect and remedy relatively small problems before they become major issues. 

Clean Sprinkler Head Nozzles To Prevent Clogs

If water is pooling at the sprinkler head and not dispersing evenly, it could be caused by dirt or debris clogging up the nozzles.

Clean these out with a garden hose fitted over the top of them for about ten seconds; if this doesn’t fix your issue, then consider replacing those parts altogether.

Check Sprinklers for Damage Regularly

Sprinklers can also get damaged due to age or weather damage- so check yours regularly so that you can notice signs of wear and tear as soon as possible.

You’ll want to inspect all fittings and connections to ensure they’re secure. Furthermore, check to see if any heads are already broken or cracked before replacing them.

Only Use Quality Parts

Never skimp on quality parts that are meant to last–particularly for sprinkler heads. It’s often cheaper to buy an entire head than individual pieces since the price is much less. Besides, an entire unit will be more effective in preventing future malfunctions due to age or wear and tear.

Replace Worn-Out Parts

If a sprinkler head is broken or cracked, it’s best to have this replaced and not simply fixed. You may find that it’s cheaper to go ahead and buy a new sprinkler head rather than buying individual parts such as the nozzle.

Use the Right Parts for Your Needs

Sprinklers often have several nozzles to distribute water evenly across a yard or garden. But if you only need certain types of sprinkler heads–then that’s what you should go ahead and use.

For instance, it may be more cost-effective to purchase rotary sprinklers instead of spray heads since the former can cover larger areas without using much water.

Inspect All Connections Regularly

You also want to ensure all connections are secure before connecting them again (i.e., twisting them off with pliers). You’ll then know if they were poorly threaded during installation or tightened too much afterward; this could cause leaks later on.

Use a Filter To Prevent Clogging

You may want to consider using a filter as part of your sprinkler system to prevent debris from clogging the pipes. Initially, it may be an additional expense. However, in the long run, doing so will save you from having to clean out the system as often.

Clean the System’s Filter Regularly

A filter is essential in any sprinkler system to keep debris from clogging up nozzles. You want to make sure this and all other filters are clean before you install them again–or else, they won’t work correctly. Besides, this will help you maintain your system for a more extended amount of time.

Install a Shutoff Valve on Your Main Line

Installing a shutoff valve on your mainline will save you time and money should any problems arise with the sprinklers, not to mention water pressure spikes due to excessive use of lawn watering systems (or just one accident).

Frequently Asked Questions

What Are the Symptoms of a Bad Sprinkler Valve?

Symptoms of a bad sprinkler valve include water not coming out, water leaking, or just spraying erratically in one specific area. If these symptoms occur, it’s usually best to call a professional for assistance, as the faulty sprinkler valve should be replaced to prevent further damage.

Typically, the professional will use a multimeter to troubleshoot these issues.

Here is a YouTube video on how to troubleshoot sprinkler valve problems:

What Happens When a Sprinkler Solenoid Goes Bad?

When a sprinkler solenoid goes bad, it can cause low water pressure and continuous running of sprinklers. This can waste up to 400 gallons (1,514.16 L) of water per hour.

Although this problem often arises from unknown causes, some telltale signs will help pinpoint the issue. For starters, suppose you notice your system seems to be operating at half speed or less than usual. 

In that case, a corroded solenoid valve may be slowing down all fluid flow through your entire system.

How Long Do Sprinkler Valves Last?

In general, a sprinkler valve will last about 15 years. But this all depends on the quality of the valve and how much it’s been used. If a sprinkler valve is working hard, you’ll want to replace it to avoid inconveniences.



I am always happy to share all my knowledge about how to keep your garden in good condition and make it special.

Recent Posts