Water Leak Detection in an Irrigation System
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 with the irrigation system.
Dedicated Irrigation Meter
In most homes the majority of water is used outside by the landscape, 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:
- If you find a sudden spike in your water bill, you are able 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.
- 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, too, which you don't owe.
- 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, then call them.
How do you pay sewage?
Look on your water bill. How are your sewage rates charged?
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 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.
How to Program Your Controller Properly
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 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.
Turn the stations on one by one. You will be looking for several indications of wasted water:
- 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.
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.
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!
Questions & Answers
How do I find an underground leak on a sprinkler drip station?
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: https://www.youtube.com/watch?v=-IxtZfFa6rI