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How to Detect a Water Leak in the Irrigation System

With a master's in sustainable development, Susette helps Southern California water agencies carry out their water conservation projects.

This ground is too soft. The lawnmower should not have been able to make that deep a furrow in this spot. There is probably an underground leak here.


Irrigation Leak Detection

Are your water bills too high? Have you replaced your fixtures and appliances with water-efficient ones and reduced your use of water to little avail? Or are you already aware that you might have leaks but don't know where they are? Most people catch indoor leaks pretty quickly, but outdoor leaks can be harder to find, especially within the irrigation system.

Dedicated Irrigation Meter

In most homes, the majority of water is used outside, where overflow feeds into the storm drains. Indoor overflow (and wastes) feed into the sewage system. In houses with large landscapes, it makes sense to measure the two uses separately. Here's why:

  1. If you find a sudden spike in your water bill, you can find out right away whether it's from extra use indoors or outdoors by testing each meter. You'll then have to check only half the area for leaks.
  2. Since sewage charges are calculated from all meter readings except dedicated irrigation meters, you may be paying too much. Check to see how sewage is billed. If it's billed by a flat charge, you're ok. If it's billed by the amount used, you may be paying sewage charges on your landscape use, which you don't owe.
  3. Once a dedicated meter is installed, check the main meter (called a mixed meter) to see how much water you normally use per month for indoor use. That's the only thing sewage should be billed on—indoor use to help maintain the public sewage system. Multiply that amount by the sewer rate charged by your water provider. If you have been paying more than that each month, the water provider may owe you money.

Some water suppliers will refund the homeowner for prior overcharges, so install the meter first, do your checks, and then call them.

Check your water meter to see if the needle moves when all water is turned off. The meter will be located somewhere between the street and the house, before the plumbing system starts (under a cover in the ground or somewhere next to the house).


How do you pay sewage?

Irrigation System Troubleshooting

The following instructions presuppose that you have a dedicated meter. If not, you can still use your house's mixed-use meter to run this check—just make sure that all water is turned off before starting, both inside and out.

Set aside a day to turn off the irrigation system to go through your checks. Find your water shutoff valve—somewhere between the house and street—and turn it off. Give it about twenty minutes for the water in the system to stop flowing. Now check your meter. Is it still running? Is the triangular/circular leak indicator showing? If yes, you have a leak.

Next, it's time to find out where that leak is. The procedure is to check the irrigation controller, then the valves, then the sprinklers. If you still haven't found it, then you'll check for underground pipe leaks, for which you may want to purchase equipment.

For the initial checks, all you will need is:

  • Paper and pencil
  • A slew of irrigation flags (small, bright, triangular flags hooked to a 6" thin metal rod that you stick in the ground)
  • Gardening gloves
  • A trowel

When you're ready, here's what you do for the first step––checking your irrigation controller.

Irrigation Controller Check

Controllers, themselves, don't leak water. What they are is an electrical clock that tells the sprinkler valves when to release water through the sprinklers and for how long. What you're checking for, when you look at the controller, is to make sure that the programming is reasonable. Sometimes, for whatever reason, a sprinkler station (collection of sprinklers under one timer) loses its programming and goes on default, which may be totally the wrong schedule for you.

My water-use audit team once found a small hotel whose controller was totally mis-scheduled—turning sprinklers on for hours at a time every Saturday, when his water supplier required them to be off. He would have been fined if they'd caught it. We reprogrammed it to a reasonable schedule and taught him how to do it too. Subsequent calculations predicted he could save 75% of his water bill from that one move alone.

Irrigation Controller: Check the programming of each station to make sure it's what works best for the plants watered by that station. Use the controller's written instructions or watch the video below.


How to Program Your Controller Properly

Read More From Dengarden

Sprinkler Valves Check

Next, locate and inspect each of your valve boxes. Are they flooded or dry? They should be dry. If they're wet, check them carefully for worn parts, loose wiring, or water leaking out between fittings. Post an alert flag next to problem boxes and leave the cover off to come back to when this check is finished.

If you are doing the repairs yourself, estimate and purchase the parts you will need and make the repairs all at once before going on to test the rest of the system. (See the valve repair video in the next section.) If you are not making repairs yourself, you might want to start a list of the problems you find for your landscaper or plumber to take care of.

Sprinkler Valves - This set had problems with leaking and electrical connections.


Sprinkler Stations Check

Once the controller and valves have been tested, it's time to start checking sprinklers. If you have a large landscape, you will need the help of another person—one to stay at or near the controller to turn stations on and off, the other to walk around the sprinklers, as they come on, and take notes. The walker should also be carrying alert flags to mark whatever problems they find for later repair.


  • Water geysers—tall spouts of water that indicate missing or broken sprayheads.
  • Floods around the base of a sprinkler. Grass may need to be cut shorter or a short riser replaced with a taller one. There could also be an old valve that is not shutting off properly, especially if a number of sprinklers in the same area are leaking. You might want to check the valve that supplies that sprinkler again.
  • Misaligned spray head shooting water into a nearby obstruction or over the sidewalk or parking lot, instead of watering grass.
  • Water spurts between sprinkler heads—indicates a broken pipe (lateral line) that has already blown out the soil above it.
  • Flooded areas between sprinklers can indicate a slow, steady leak in a lateral line underground. You will have to dig down to find the actual spot. (See next section.)
  • Spurts of water at the base of a sprinkler––indicates a broken seal where the nozzle or riser meets the supply line beneath.

All of these problems are commonly found with large landscapes. They need to be checked for and fixed on a regular basis, at least once a month. Routine maintenance, in itself, will save you water. Once all the stations have been checked and repairs made, you can test the irrigation meter again.

In the majority of cases, this is all you will need to do. But if the meter is still showing water being used, even when all water is off, you may have an invisible leak underground. In that case, you can run through the following steps with or without the equipment shown in the next section. Having the equipment makes it easier.

Leak Detection Tools

If you insist on finding the underground leak yourself—for the challenge, perspicacity, thrift, or just plain stubbornness—you may want some specialized tools:

  • Water Leak Microphone: This is a rod that you pass over the ground, or probe through it in spots, that magnifies the sound of water rushing through pipes. Once you understand what all the sounds mean, you can follow the water sound to where its intensity increases to find the leak.
  • Leak Noise Logger: The hand-held logger is attached to the microphone probe. It records the intensity of sounds the microphone picks up. If you find it hard to determine in which direction the sound grows louder, look at the digital readout of your logger.
  • Headphones: The purpose of headphones is to close out ambient sound and let you focus on what is being transmitted to you from the leak detection probe.
  • Electro-Acoustic Testing Kit: This kit provides all of the above––a leak detection rod, reader/logger, and headphones to locate underground leaks with plastic or metal pipes. The testing rod detects the sound of water rushing through a pipe and helps you locate the source. It passes what it "hears" through a wire to your hand-held reader and to your headphones. By tracking the intensity of the sound, indicated on the reader, you can home in on the leak.
  • Garden Shovel: You'll use a shovel to dig around the pipe once you've pinpointed the location.
Finding leaks: Some leaks are pretty easy to find. Others you may have to use equipment to locate.


Underground Plumbing Check

Start with a meter check again. Turn all the water off that is measured by the meter. Wait several minutes, then check the needle. If the needle is still moving, then this time, you will need to check for water pressure and the sound of running pipes:

  • Turn the stations on again, one by one, starting with the one closest to the main pipe where water comes into your property—usually located near the meter itself.
  • Look at the difference in water pressure (the height and size of spray) between the station closest to the main pipe and the one next to it. If there is any difference at all, it should be a barely noticeable lessening as you go further and further back into the property. Test all of your stations this way, comparing the water pressure of one set of sprinklers with those of the station after it.
  • If you have a hidden leak, at some point, there will likely be a noticeable drop in water pressure. This means that some water is leaving the pipe in that station before reaching the sprinklers. If the entire station is noticeably lower, the leak is probably fairly close to the beginning of that station. If it doesn't get lower until closer to the end, then that's where the leak is—near the end.
  • Sometimes the water gushing through pipes will be loud enough that, if your hearing is good, you can actually hear where the leak is. If not, this is where your equipment comes in. The microphone will pick up and magnify the sound of the water (or the pipe vibrating with it), and the meter in your hand will read the intensity of the sound as you move along the pipe. The most intense reading is likely the location of the leak. Flag it.
Water Pressure Test: In this case, there appear to be no leaks, although there are problems with poor coverage.


Pinpoint the Exact Location

Once you think you have a location identified, turn the water off and take a shovel over to test the ground. These are indications that you are in the right spot:

  • The ground will likely be soggy, so look for that first. Mushrooms growing in that location and nowhere else are another potential indicator.
  • If you don't have equipment, you will probably have to dig down in a few locations to find the exact location of the leak. When you think you're close, manually turn the valve that goes to that area on low. You want dribbles coming out of all the sprinkler heads, not a spray. This prevents water and mud from suddenly gushing up into your face when you've uncovered the leak with your shovel.
  • Keep digging around the area, looking for the difference in soil moisture. When you find the leak, fix it. Then test the meter and that area (if you need to) again.

Water Provider Assistance

If you have tested all of your stations and water pressure seems the same, if you have found no floods and no area-specific patches of mushrooms or especially green grass, and you've heard no sounds of water leaking underground, but the meter is still running when all the water is off, then there may be a problem with the meter itself. In that case, you will need to call your water provider.

Tell them all of the tests you've run and ask them to send someone over to check the meter. If it's an old meter, there could be something wrong with it. If it's a newer meter, it could have been improperly installed. If everything is ok when they check, it's time to call a plumber.

Whatever results and whoever pays, you will still have benefitted by each problem discovered and fixed in the process of locating the leak.

Water Use Audit

You can benefit still further by calling for a water audit. A water audit will show you what kinds of fixtures can be retrofitted to use less water automatically and will provide you with a landscape watering schedule tailored to your area and the types of plants you have. Some water suppliers give audits free of charge, so be sure to ask while their technician is there checking the meter. Many suppliers also offer a complete indoor-outdoor audit as part of their water conservation program. It wouldn't hurt to ask about that too. Good luck!

Conducting an outdoor water audit will show you many alterations you can make to conserve water. Most of them will make your plants healthier too.



Questions & Answers

Question: How do I find an underground leak on a sprinkler drip station?

Answer: I assume you've already tested to make sure there is a leak somewhere. The most obvious next step would be to look at your plants and the ground around them. Look for extra green spots and soil that is wetter than it should be. Here's a pretty clear video that shows another way for locating and repairing drip line leaks:

Question: With the irrigation valve on, water runs through my main pipes to the valves, and if the valves are operating correctly, water does not go to the sprinklers. All my boxes are dry, and there is no indication of leaking at the sprinkler heads or soggy ground. Is it possible that there is a leak in the pipe(s) going to the valves? If so, how do I find that leak?

Answer: If your sprinklers are not getting water and the zone valve boxes are dry, there are two possibilities:

1. The valves could be blocked. Maybe a diaphram inside has gone bad, or the wiring is damaged. Check all your valves to see how many are allowing water through when they're open.

2. If only one is a problem, there could be a leak in the pipe between the shutoff valve (the main valve to the sprinkler system) and the zone valve in question, which is what you're asking. That's going to be trickier. I would call a plumber for that.

Question: Can you still have a leak if you have shut off all the water in the house and the sprinklers are off but when you check the low flow meter it's not moving? I have done that and the low flow meter is never moving, but in the last 13 hours, it says that I used 1.06 ccf of water, even though all I did was use the toilet once and do the dishes once. They say I am just using high amounts of water but I am barely even home and live alone.

Answer: So you're using between 7–8 gallons of water in that time. How old is your toilet? Old toilets can use up to 7 gallons with each flush. You might want to check and see, then have it replaced with a newer one that uses 1.28 gallons or less per flush. Here's an informative article about toilets.

Question: I replaced my irrigation system in April, 2018. I use ground water, so a underground pump feeds the manifold. Since then, half of my backyard is constantly muddy, not just wet. The other half of my backyard is wet, but not as muddy. I have not used the backyard sprinklers for two months because of this problem. The company who installed the new system has tried to figure out the problem, but to date, have not. What is causing this?

Answer: Your description sounds like either the annular space around the well casing was not sealed properly or the well casing, itself, has sprung a leak. You might also check the pipe leading from the well to your irrigation system to make sure it was sealed properly. Let me know if you've already checked these and your yard is still flooding.

Question: Meter on, irrigation control off. Water department states I’m using a massive amount of water several times in a 24 hour period. Any ideas?

Answer: "Several times in a 24 hour period"? Is the water department coming out several times a day or are you on an Advanced Metering system––where the water department can read your meter from their office, i.e. how do they know it's several times a day?

How big is your landscape? Could it be that you have another sprinkler controller you didn't know about that isn't hooked up to the main one? Or is there a water use in the house that's set on a timer that's going awry? How often do you use your clothes washer? Could there be a leak in the supply pipes there?

To start with, test the meter to see whether the water bursts are coming from the irrigation or the house. Then look for anything connected to timers. The following article is written for buildings with facilities maintenance crews, but it might give you some tips.

Question: I cracked a pipe while digging, but I don't use the irrigation system will water leak if it's not used?

Answer: It sounds like your outdoor faucets are not connected to the irrigation system, so the only way it would really matter is if you sold the house and forgot to fix the pipe first. Then your buyers would have problems with the irrigation system. To make sure there are no problems for yourself, you can find the valve that leads to the irrigation system and shut it off.

Question: We replaced the Stop & Waste Valve for our sprinkler system. The water company shows we are losing 2.5 gals water somewhere per hour. When we turn the sprinkler valve off, no leakage registers. The ground is wet, but there's no standing water around the valves or around sprinkler heads. No wet spots in the landscaping either. Could the new shutoff valve be leaking—the part that goes into the sprinkler system when all zones are off? Any ideas would be helpful.

Answer: If no leakage registers when the valve is off, that's a good indication it could be the valve or something right around it. I have some questions, then I'll give you a video to watch. 1–When you first took out the old valve, how was the T where you remove it from? Was it corroded? Could it have needed replacement too? 2–When you installed the nipples that enter and leave the valve, did you use a good paste to seal them with? 3–Did you use a female adapter made of PVC? You may have accidentally cracked it and caused a leak. Watch this video and maybe it will help.

Question: I installed a new irrigation system last year. This year I turned the main system valve on. Why is no water going to my valve body?

Answer: It sounds like you might have another valve that's only for the irrigation system, or is that what you mean by the "main system valve"? It should be located between the main water valve and your controller, and it would need to be opened too. Otherwise, you're looking at debris or blockage in the pipes, although you should be seeing a little water flow in that case.

If you had a professional company install your system, ask them for a diagram of where all the valves are located. They should have provided one already. If you did it yourself, it might be a good idea to make a diagram for yourself and include the location of the stations and sprinklers––maybe color code the sprinklers that go with each station. This will help you make repairs in the future.


Susette Horspool (author) from Pasadena CA on August 06, 2019:

@John—We now have a question and answer section, as you'll see above. The reason I'm referring you to it is because many other questions have been asked along those lines, enough so that it has a page of its own now, where any reader who has questions can go first, before asking their own. We like to keep them all together, in case future readers have your same question. Please ask your question there. Thanks much.

John Birckbichler on August 05, 2019:

I have an automated underground watering system that uses well water and I know I have a leak somewhere but cannot find it. I understand that the system is pressurized to the solenoid valves and there is no pressure beyond them until the solenoid is activated, correct? I also have two additional hose bib lines, on the same system, but external of the solenoids that are activated manually. The valve box is dry, I have no wet spots in the garden, but the pump cycles on and off every few minutes in order to maintain the set pressure. Could I have a bad check valve on the inlet side of the pump? If not, what other areas should I investigate?

John kelly on September 24, 2018:

All sprinkler working except zone 5 all 4 of the valves have been repaired but zone 5 not working

Susette Horspool (author) from Pasadena CA on July 28, 2018:

Bummer, Bill! Turning off the valve should have stopped water from accessing the leak but, of course, if it didn't then the valve must be broken too. Most properties only have one main shutoff valve that turns off water to the entire property. Does that one not work for your leaking system? Or are you looking past it for a smaller supply shutoff valve that leads to the irrigation system itself?

If you haven't found it by listening for the water flow, you might want to purchase a testing kit, so you can better hear the sound of water rushing through the pipes. Then you'd trace that sound backwards along the pipes until you find the shutoff valve you're looking for. Otherwise, you can take the easy way out and call a plumber. :D

Bill on July 28, 2018:

In May 2015 we bought this home. We realized that an old irrigation system's underground pipe was leaking and we turned a rusty underground valve off near the leak. Unfortunately couldn't find a box or shutoff for this system. Now the leak is nearly a geyser. I wish we could find a shutoff.

Verne Strong on January 25, 2017:

Fantastic article. We are using 200- 260% more water each month than last year to irrigate our front yards on our street of 34 homes. Now you have given us some vital tools to try to discover the problem. Thank you

Susette Horspool (author) from Pasadena CA on November 19, 2012:

Check the water meter. That's a dead giveaway. You can't have a leak without the water meter showing it. For a quick refresher:

* Identify which stations go with which meter (if you have more than one) or be prepared to check all meters at once.

* Turn all water off that's measured by that meter (or all of them) for about 20 minutes.

* Check the meter gauge/s to see if the needle or counter is moving. If it is, it means water is being used even with all the water off, i.e. you have a leak somewhere.

cooper cook on November 19, 2012:

I don't know if this is a commonly asked question or not, but is their a way to tell if your irrigation systems start acting up or be able to tell if they have a leak before it gets out of control? Because a lot of the websites I've been to only say how to fix it when it's usually worst case scenario, and I'd like to try to avoid having worst case scenario.

Leah Lefler from Western New York on August 22, 2012:

This is so important to conserving water and lowering the water bill, watergeek! We don't have a sewer system (we're hooked up to septic), so we don't have a bill for that particular utility. We always monitor our taps to be sure they aren't leaking!

furniturez from Washington on August 08, 2012:

Definitely going to lower my bill... I can't thank you enough!

Kristi Sharp from Born in Missouri. Raised in Minnesota. on August 07, 2012:

No, but I should. It's a little robot shaped like a beetle. He lives in his own little garage in the yard. He's programmed to come out two times a day - depending on how long the grass is, or if it rains and he mows the yard. I'll have to check into that! Thanks

Susette Horspool (author) from Pasadena CA on August 07, 2012:

A robotic lawnmower? How does that work? Have you written a hub about it, by chance?


Ugh, me too. Or that we sell the robot :)........


You're welcome. I hope it helps your husband and that you save a lot of money on your water bill.


I'm going to print this for my husband because we have a sprinkler system, a robotic lawnmower - a pretty big yard - and every month he is (cursing) upset about the water bill being high. I would love to be able to save some money if we can. Thanks for sharing this. -K

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