Sprinklers Won't Turn Off? (Here's What You Should Do)

Ryan Womeldorf
by Ryan Womeldorf

Having a sprinkler system for your yard can be a beneficial thing. Keeping your garden and landscaping looking lush and healthy is a difficult job and a sprinkler can ease the burden. It can be especially helpful for larger properties.

But there are times where the sprinkler simply won’t shut off. When this happens, there are several possible causes and fixes for those issues. If you have a Rain Bird sprinkler in particular, there is a fix to that problem as well as adjust the sprinkler heads.

This guide will walk you through the reasons why your sprinkler may not be working and what to do to alleviate the issue, saving you the hassle of higher water bills and a yard with overflow.

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Why the Sprinklers Won’t Turn Off

The simplest explanation for why your sprinklers may continue running is that there is something keeping the valves from closing. There are many different reasons that this could happen, but that is the quick explanation.

When an issue arises, you will want to cut the flow of water off as soon as you can. This will save your landscaping from overwatering and give you the time that you need to locate the problem and fix it before turning the water back on.

Shut it Down Using a Controller

In some cases, you will be able to simply shut down the entirety of your sprinkler system using a controller or control box. This is the simplest way to shut down the sprinkler so that you can investigate the problem further and locate the root cause.

Locate the “off” switch on the controller or the panel (this can be different depending on the controller that you have, but they are all similar). This should at least turn off the flow of water from your system for the time being.

If this doesn’t solve the issue, you are facing some sort of mechanical issue. When a mechanical issue is the problem, that means that you have to turn the water off at the water source to stop it from flowing out of the valves.

Shutting Down Your Sprinkler Manually

When the controller or control box are no longer working in a way that you can simply shut off the valves, you will have to go to the source of water for your system. By turning off the water at the source, it will completely cut off water flow to the entirety of your sprinkler system. Best of all, it won’t cut water to your home.

It is important that you locate the manual shutoff as soon as you can. Continued water flow can potentially overwater flowers or grass and will just rack up your water bill if left unchecked for too an extended period of time.

Backflow Prevention

There are also backflow prevention devices that can be used as the shut off point for your system. When looking for the backflow, you’ll look for a green rectangle; this is the box that will have the backflow device in it. In older units, the box itself may be more of an oval shape.

You can generally find the backflow prevention closer to the road that is located near your property and definitely in range of your water meter. There are also instances where the backflow can be above ground depending on the system.

Shutoff Valves

There are also a pair of valves that could be available to act as manual shutoffs. Generally speaking, these are either a gate or ball valve. Generally speaking, backflow prevention devices will have a ball valve, though there are older units that can have a gate valve.

Most of the time, all you need to do is to close the valve to prevent further water flow to your sprinkler system. Doing it at this point will shut off water to the sprinkler but it won’t impact the rest of the home.

Be careful when you turn these valves and wear gloves if you have them. The valves will be difficult to rotate and could be rusty, leaving your hands dirty and can even lead to potential injury if you don’t take precautions to protect yourself.

Air in the Valves

One of the main reasons that your valves aren’t shutting could be that there is air trapped. Even a small bubble of air can become trapped because the water ports of the valve are quite small. This will stop water from flowing through that port.

The water itself, flowing through the port, is what keeps your valve diaphragm from opening. As a result, the valve will remain open. You will need to go to your manual controls on the valve and essentially “burp” the bubble out.

When you have successfully cleared out the air bubble, it should allow the valve to close properly once again.

Controller Not Working or Programmed Wrong

Another common reason that your sprinklers may not be turning off is that the controller to the system is either not working or programmed wrong. This is especially true when programming schedule times for your sprinklers to run.

Check out your controller first to see if your sequencing and timing is set to run all at the same time. A simple reprogram can fix that problem, provided your remote or control panel is still working the way that it is supposed to.

The Valves Have Worn Out

With your water supply off, you can begin to inspect the individual valves to see if they are still structurally sound. There are times where the valves themselves can wear down or even break; this will result in them being unable to close and water will continue to flow.

Inspect each valve, even if you are confident that you have found the culprit. You never know if there may be multiple units that are busted until you check. And it would be quite annoying to get through the process of replacing a broken valve only to find out that there are others causing a problem, too.

Replacing a Faulty Valve

In most cases, this should be a job left to the professionals. Replacing the valve can be a tricky proposition, particularly if you have never done it before. But if you plan to replace the valve yourself, it is imperative that you pick up the right parts before beginning.

While a sprinkler valve should last for 5-10 years, they can wear down and an improperly installed valve will likely fail far sooner (1-3 years or so). Depending on the manufacturer of your sprinkler, you can find tutorials on how to appropriately replace that faulty valve.

Loose or Open Solenoid

In a sprinkler system, the solenoid is something of a manual control so that you can open the valve manually. This is so it can be operated as a bypass when the controller isn’t working right. The solenoid is particularly useful during the winter or events where you need to drain the system.

Generally, you twist the solenoid clockwise to close it; if it is loose or damaged, it likely will not close the way that it normally does. If the solenoid is loose, look into replacing it as soon as possible. This should solve the problem of the sprinkler continuously running.

Debris in the Valve or Solenoid

When it comes to the valves and solenoid, if they are not allowed to close properly, the water will continue to flow freely. One of the leading causes of the valve or solenoid not closing is that there is debris prohibiting it from closing entirely.

And given that there are rocks, soil, and loose debris around the valves and solenoid, this could be the reason that they are not closing. Your system will leak at best and flow freely at worst. The solenoid is on top of the valve and generally runs through electrical signals that come from your controller.

If you can’t manually close the solenoid, there is a good chance that there is some loose debris in there that is gumming up the works. Give it a thorough cleaning and it can being to work properly once again. If the water continues to flow, there are issues elsewhere.

A Busted O-Ring

There are other parts that are integral to the working condition of your sprinkler system. Valves and solenoids use an O-ring to create an air/watertight seal that prevents leaking or unauthorized water flow.

One of the leading causes of leaking is because the O-ring is at fault in some way. It could be as simple as the O-ring not being properly seated on the solenoid; this will require some adjustment to remedy the issue.

But there are times where the O-ring can be distorted, damaged, or broken entirely. When this is the case, it will need to be replaced. Inspect the solenoid, pull out the O-ring, and replace it if that is necessary. Make sure that the O-ring is clean as well; any debris between it and the solenoid will prevent it from seating properly.

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How to Identify the Problem

It can be difficult to determine what might be causing your sprinkler system to not turn off. With that said, your best course of action is to turn off the water supply and possibly enlist the help of a professional. They will be able to assess the issue and provide solutions to correct it.

However, it is possible that the valves have some dirt and debris trapped inside. Check if the valves are clogged and could benefit from a good cleaning. If they are clean, they may be broken or cracked. In this case, they can easily be replaced with some additional parts from your local hardware center.

Other possible reasons for your sprinkler system not turning off include a simple scheduling error, faulty solenoid, or a busted o-ring. If your own efforts fail, or you’re not confident in your repair abilities, consider having an irrigation company assess and fix the problem for you. That way, you’ll be saving yourself on water – and therefore, money.

Ryan Womeldorf
Ryan Womeldorf

Ryan Womeldorf has more than a decade of experience writing. He loves to blog about construction, plumbing, and other home topics. Ryan also loves hockey and a lifelong Buffalo sports fan.

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