How to Locate a Buried Valve

If you have an underground sprinkler system (drip systems too), somewhere out in your yard there are buried pipes, wires, and maybe even valves.  But where are they?  Sometimes they are above ground, so all you need to do is look around a bit.  If not, then they aren’t visible because they are buried.  (Big sigh.)  You have perhaps the toughest problem there is in the irrigation repair business.  There are no easy and inexpensive ways to find a valve, pipe, or wire.  While this article addresses primarily valves, the methods for finding pipes or wires are basically the same.

Before we get going on how to find a valve let me make a couple of comments about what to do when you do find it.

Digging it Up

Once you find the valve you will probably need to dig it up.  If you’re lucky it will be in a valve box and the box will not have been filled with dirt by some gopher.  If there is a box be prepared to find critters inside the box when you open it!  Use a shovel to pry the lid off from a safer distance.  If the valve is not in a box, you need to be really careful when digging.  Electric solenoid valves have wires attached to them that are very easy to cut with a shovel and very hard to repair once cut.  Also if you hit the solenoid with a shovel you will probably break it and possibly break the valve as well.  Even the valve body is easily cut as well as the pipe.  So go slow and easy.  Dig around the valve using a hand trowel.  Better yet (I know this makes a mess!) you can use the stream from a garden hose with a patio cleaning nozzle on it to dig and use the water blast to loosen the dirt around the valve and wires.  A plastic drink cup (ie; a McDonald’s cup) works good scoop out the muddy water and is unlikely to damage the valve.

If you cut or even nick the insulation on a wire, splice it back together using a water-proof splice kit made for underground wire splices.  It is really important that the bare metal not be exposed to soil or water.  Electrical tape alone will NOT work as a splice water-proofer!  If the metal wire itself is not damaged you can seal the damaged insulation on the wire by coating the damaged area with several thick layers of PVC cement (glue).  Let it dry then wrap the entire area tightly with plastic electrical tape, extending several inches beyond the damaged insulation.  Then coat the tape with pvc cement.  This is not the best solution, but it usually works.

If the metal wire is damaged (even if it is just partially cut) you need to cut out the damaged section and splice in a new section of wire.  Use special water-proof splice connectors you can buy at any hardware store for ALL your irrigation wire splices and connections.   Even ones above ground!  If any water leaks into the splice it will corrode the wire.  Even if the wire is not corroded through, the corrosion can block enough electric current to make the valve not open.  If the wire breaks or corrodes it will be a major pain to find where the problem area in the wire is.  You will probably have to replace all of the wire.  You do not want to have to do that!  Water-proof those splices.  Got it?

I strongly recommend that if you splice or repair a underground wire you put a valve box over the repair rather than just burying it.  Any splice or wire repair is going to be a likely source of future problems.  The box will help protect it and will allow you to more easily locate the splice/repair in the future if you should have problems.  If you can’t put a box over it put something else there that will help you locate it, like a metal tent stake driven fully into the ground at the splice location.  You can find the stake with a metal detector.  Make a note diagramming the location of the splice/repair and put it in the irrigation controller case.

Be Prepared to Replace the Valve

There is a pretty good chance that if you can’t find the valve you will need to replace or repair it when you do.  That’s just how the odds stack up.  If the system is in such bad shape that you can’t find the valves, usually the valves are in bad shape also.  So prepare yourself now for that expense and effort.

Box It!

Once you find your valve, put a valve box around it!  Irrigation valves are often marketed as “direct-burial”, but as you now know (or will soon discover), finding one that has been buried directly in the dirt is very difficult.  It doesn’t need to be a big fancy box, they make nice little inexpensive ones that work fine.  Even a used plastic bucket or gallon size paint can flipped upside down will make a decent temporary valve box until you can afford something better.  It just isn’t a good idea to bury a solenoid valve directly in dirt.  Besides the problem of finding it later, burying it can also make it fail faster.  Plus you are a lot more likely to damage a valve buried in dirt when you dig it up for repairs.  And all valves are going to need to be repaired someday!  So put those underground valves in boxes, and while you’re at it, put 4″ of gravel under the box!  The gravel keeps gophers from digging into the box from underneath and filling the box with dirt.  You can buy a small bag of gravel at most home improvement stores.   (Decorative rock works also, especially that rough surface lava rock.) You might also want to measure and write down where the box is located as measured from a couple of fixed locations, such as a house wall or fence.  That helps you find it if grass grows over the top of it… if you don’t lose the measurements!

OK, time to get to work.


How to Find a Buried Valve

1. Start by trying to figure out what the most likely place is where the valve would be installed.  To do this you need to try to “get inside the head” of whomever originally installed the system.   This helps cut down the “search area”. Do you know where other valves are in the yard?  Are they each inside the area they water? If so, the others are probably inside the area they water also.  Are they grouped together?  Then the others may be nearby.  Maybe there is a pattern to the placement of the valves, all on one side of the yard perhaps, or all in a row?   If you don’t know where any of the valves are, you still know a pipe takes water to them.  Find where that pipe connects to your water supply.  Now try to figure out which way the pipe goes from there.  Sometimes if you look real close you can see a slight indentation in the soil where the trench for the pipe was dug.  Another tip, the grass is often just slightly greener where the trench was dug.  For lawns, if you mow the grass short and look across the surface you can often see slight “troughs” where the trenches were dug and the soil has settled.

If you have the original plans for the sprinkler system they may help you find the valves, pipes and wire locations.  If this is a commercial irrigation system the local building inspector or planning department may have a copy of the plans.  However, even if you do have the plans, chances are the valves aren’t located where the plans show them.  So I wouldn’t waste too much time looking for plans.  In 35 years of practice and thousands of irrigation systems, I seldom saw the contractors install the valves exactly where they were shown on my plans.  Even when I required my contractors to label and dimension the valve locations, I often discovered they just made up the dimensions!!   At best a plan might give you a hint as to where to look.

2. If the valve you are looking for is an electric valve that actually still works, try turning the valve on and see if you can hear the solenoid buzzing or water whizzing through the valve. Try using a mechanic’s stethoscope placed on the ground to listen.  Or cut the bottom out of a paper cup, place it upside down on the ground, and put your ear over the top.  Do this late at night or in early morning to reduce background noise and make it easier to hear. Note; if the neighbors see you they will think you’ve lost your mind!

3. Try a metal detector if you own or can borrow one.  I’ve honestly never tried this, but some people tell me it works, and it seems logical.  Most valves have at least a little metal in them, although the cheapest ones have very little.  The solenoid on an automatic valve has a bit of metal in it also.  If you have, or can borrow, a metal detector you may be able to locate the valve or the wires with it.   If the valve or wire are buried deep, a low cost metal detector will probably not find them. In my opinion the chances of success using a metal detector probably are not good enough to make it worth the expense of buying one. But if you have one or can borrow one, why not try it? I’d love to get your feedback on use of a metal detector if you try it!

Try following the pipe to the valve using a metal detector.  According to reader James P. you can trace the location of a pipe using a metal detector and a “fishing tape” (aka; draw wire or draw tape).  A fishing tape is a long tape used by electricians, they inserted the tape into conduits to pull wires through them.  The tape needs to be metal or at least it needs to have a metal section at the end of the tape that you can detect.  You need to cut the pipe open, then you insert the tape into the pipe.  A high-quality metal detector (he warns the cheap ones aren’t powerful enough) can then be used to trace the location of the end of the tape from the ground surface.  You may have to follow the route in sections depending on the length of the tape.  Also if there are any tees or ells in the pipe the tape will not easily slide past them, so you may need to dig a few potholes to cut into each new section of pipe after a tee or ell.  Repair the sections of pipe you cut out to insert the tape using repair couplings or compression couplings.  You will find these at any hardware or home improvement store.

4. Use a valve chatterer. This won’t work if the wires to the valve are cut or broken. So if you’re trying to find an automatic valve that won’t open, a chatterer is not likely going to help.  A chatterer is a electrical device you put on the valve wire that makes the valve rapidly turn on and off.  The result is that some brands of solenoid make a loud clicking or chattering sound that will give away it’s location.  Unfortunately some valve brands don’t make much noise at all. And the deeper the valve is buried, the harder it will be to hear it chatter. Most irrigation pro’s have valve testers that include a chatter function along with other testing tools.  These are handy tool for diagnosing valve electrical problems, but tend to be priced beyond what is justifiable for a homeowner to buy.  (See ads for typical chattering devices at right. Also see my review of the Armada Pro48, which is the one I use.)  To use a chatterer you disconnect the valve’s wires from the controller/timer and hook them up to the chatterer device. Turn the chatterer on and the valve should rapidly open and close and create a noise.  Just like with listening for the water running through the pipe, you will have to go out in the yard and listen for the chattering, and it will help if it is during a quiet time of the day.

Make your own chatterer.  All you will need is three 9-volt batteries and a friend with dexterous fingers.  Someone who texts a lot on their phone is perfect!  Start by making a valve actuator. Here’s how to make one out of three 9-volt batteries.  To chatter the valve simply attach one of the valve wires to one terminal of your home-made actuator and tap the other wire against the other terminal of the actuator.  Tap the wire at one second intervals. It doesn’t matter which wire goes to which terminal. The valve should turn on and off with each tap and make a clicking sound.  I don’t recommend tapping the wires on the controller/timer terminals to chatter the valves. If you slip up while trying to tap the wires against the terminals and short circuit the wires you can damage the controller/timer.  Destroying an expensive controller will ruin your day!

5. Water Dowsing,  aka; water witching.  This is a method of finding a water filled pipe by walking slowly while holding a branched stick or a couple of bent wires in your hands.  I won’t try to explain how to do it, you can look it up if you want to try it.  I’ve never witnessed it done successfully firsthand.  But I have met several people over the years who have either seen it done successfully or done it themselves successfully.  This includes people I trust, so I’m not in doubt of their claims.  Did they see or do what they thought they did?  The answer to that thorny question I will leave to you to decide!

OK, the science behind dowsing is very shaky- at best.  Most explanations I have heard are that those with the talent are able to read subtle signs on the ground surface that indicate the location of water or the pipe.  They then subconsciously transfer that information to the movements of the sticks, like a Ouija Game.  Maybe.  But most of those I’ve talked to say that the force on the stick/wire is very strong and not likely to be from anything subconscious.

Everyone I know who claims dowsing works or that they have the ability to do it IS an expert who has worked in the industry many years.  I can tell you that with 35 years of experience I can often look at an irrigated area and tell you where the pipes are with reasonable accuracy.  No sticks needed.  Just lots of experience looking at irrigation systems, and hints like those I’ve already covered, dips in the ground surface where trenches have settled, areas that are greener than others, etc.    At any rate, I don’t want to get into any arguments over dowsing.  I present it as an option that many believe works.  If you can find someone with the talent, they may, or may not, be able to help you find the pipes, valves, or wires (yes, some dowsers claim they can find wires too!)

6. Use a wire locator (aka; wire tracer) device. This is how the pros do it, but if you notice the cost of a wire locator (ads on right), you will probably find that if you are a homeowner it is not within your budget! Some tool rental places, especially those that cater to professional contractors, have wire tracers they rent.  (Sprinkler Warehouse rents wire tracers using overnight shipment.) You use a wire tracer to follow the path of the wires to the valve, starting at the controller/timer. Again, if the wire is broken you may not be able to follow it (although the better units can even jump the signal over small wire breaks.  However, it will find the location of the break so you can repair the break in the wire.  Then you can continue tracing the wire to the valve– or the next break in the wire! )  Also be aware that it takes a bit of practice to use a wire tracer, but it can be mastered in a few hours.  The way it works is that you attach a signal generator attached to the valve wire.  Then you use a receiver that senses the signal.  The receiver beeps when you are near the wire.    A word of warning on wire tracers. You need a tracer with a signal generator that is powerful enough for the sensor to be able to pick up the signal through 24″of dirt depth. While most residential irrigation wires are not installed that deep, they are supposed to be!  The wire tracers made for use by electricians to find wires in house walls are not powerful enough to detect buried wires, even if they are only a few inches deep. I have one made for detecting wires in walls, that also lists irrigation systems as a suitable use, and it will NOT detect wires buried even 1″ below ground!!!  So before you spend money, make sure the device is suitable for wires that are buried underground.

Hey, do you know someone who works as a line-person for a phone or cable company?  They may have access to a wire locator since they often use them for repairs.  Maybe this weekend they might trade a few minutes of their time for a couple of beers?  hmmmm?

Now for the “this is a lot of work” solutions!  Start with a trip to the store to stock up on Advil and Ben-Gay.
7. Probing for valve boxes.  Before you try digging, first try a shallow probe for valve boxes. If valve boxes were placed over the valves when the system was installed, they are probably just below the surface. Often the only reason you can’t see them is that grass grew over the top of them. A pitch fork is ideal for probing for the boxes, just gently stab the ground until you hear the clunk of a fork tine hitting the plastic box top. If you don’t have a pitch fork a metal yard rake works for some people (others can’t get the motion right to plant the rake tines through the grass), a stick with a long nail-spike on the end of it works good to probe the ground, and last resort is to use a screwdriver on your hands and knees (ouch!)  Again, use logic to figure out the best place to start probing.

8. Probe or dig to find the pipes. (My back is hurting just from writing about it.)  If no valve boxes were used, then you will need to probe deeper. Now, just to warn you, it is highly likely you will cut or break a pipe or wire while you are doing this.  So just be prepared for that as a cost of the process of finding the valve.  OK.  Fortunately installers who don’t use valve boxes also tend to not bury the pipe and valves very deep, cause they’re lazy and cheap.  Normally the pipe from the water supply to the valve is buried deeper than the pipe from the valve to the sprinkler heads. (This pipe is called the “mainline” and is supposed to be at least 18 inches deep!) Plus the wires normally are thrown in the same trench with that mainline pipe going to the valves, and you don’t want to cut or nick a wire with a screwdriver blade.  So it’s best to start at a sprinkler head and work backwards toward the valve.  Use a long blade screwdriver to gently probe for the pipe around the sprinkler.  Try to pick a sprinkler head you think might be close to the valve. If you can turn on the sprinklers, the one closest to the valve will often come on slightly quicker than the others, and have more pressure, so it will have a more “powerful” sound and forceful spray when it is operating. Be gentle when probing, don’t break or pierce the pipe! Once you find the pipe keep probing and follow it back to the valve.  If the ground is really dry and hard, you might want to water it to soften it up first. As you follow the pipe consider marking the pipe locations on the grass or dirt using some of that special marking spray paint or the little sprinler flags they sell at irrigation supply stores.  Marking the pipe location will help you track where you found pipes (ie; this could be a multi-day project!)  Tip;  draw yourself a diagram of the sprinkler pipe locations for future use as you find out where the pipes are!

What if you can’t find the pipes with a screwdriver? Well, in that case it’s time for a shovel. Have fun digging up the yard! 🙁