Finding Leaks in Sprinkler Zones and Common Problems

bad sprinklerRecognizing a water leaks within a sprinkler zone can be  difficult as they may not reveal their location until  under pressure.

How do  you recognize a minor leak  in the sprinkler zone if it’s not obvious?

  1. The first noticeable trait would be the zone does not appear to cover the ground as well as it used to. You may also recognize plant material or turf that appears dry or starving for water.
  2. Moist mucky dirt, soggy spongy area(s) in the yard. Someplace that never seems to be dry.
  3. New or additional brown patches  in the turf indicating low water coverage.

If you have read any of my sprinkler articles you know that most sprinkler problems are with heads and valves. Both provide obvious indicators of water loss. Here is a recap of the most common problems: 

  1. Weeping heads: A slight amount of water is passing through the valve when it should be closed. The sprinkler heads remain wet well after the sprinklers have run. Typically, disassembling the valve and cleaning will correct it.
  2. Dirty heads: Dirt, pebbles and grunge can lodge itself in the sprinkler nozzle as well as the body and shaft of the sprinkler head. These problems will modifiy the pattern, providing excessive water in the wrong places. Start by replacing or disassembling the head and cleaning it.  TIP: Like for like heads and nozzles will reduce complications in future repairs. When a sprinkler zone is turned off,  typically the lowest head in the zone becomes the relief valve causing water left in the lines to drain out. This is very normal. However, in doing so, a suction is created that can pull in surface water, and dirt from around the other heads. This dirt can migrate throughout the zone clogging the other heads. TIP: If the location of the low head is in a bad place, an in-line drain can be installed in the pipe, but you will have to dig up the pipe to do it.
  3. Broken head: Obvious water spray outside the defined pattern. This can be corrected by replacing the head or the broken parts.  TIP: Keep extra sprinkler heads to replace bad ones. Rebuild the old ones if you can. Remember to reuse or replace the nozzle like for like. Many times you can replace the entire head without disturbing the surrounding dirt. This reduces the opportunity of allowing new dirt into the system and keep you from having to to dig the head up. 
  4. Lawn butchers: Weed Eaters and edgers are the death of lawn sprinklers. They can easily destroy several heads over a season of mowing.
  5. Allowing dirt in the system: No different than the water system in your house, allowing dirt in the pipes creates opportunities to clog valves and heads, creating more work for you. When working on sprinkler heads and valves avoid this by taking the appropriate steps  to stop surface water back into the system. When you run a zone and identify a head that needs attention, removing the head may create a suction that will pull water and dirt into the pipes. Admittedly more work, by digging up the dirt from around the head and getting the hole deeper than the head connection can reduce the opportunitiy of allowing dirty water into the sprinkler system. TIP: If there is no standing water at the head, attempt to change it without digging it up as described in number #3, this will save you some time.

If you have corrected the problems associated with the above list and you still have problems, its time to look deeper into the system. Most likely, if you have gone this far you are recognizing that a specific zone does not present the same pressure, or cover its area as well as the others.  This trait is an indication of a pipe, joint or fitting leak, and the leak is large enough to reduce the zone pressure but not enough to create a pool or hole in the lawn. 

water poolTry this method to further isolate the leak:

  1. Assuming you have pop-up type heads, adjust the screw on the top of the nozzle  (on every head in the active zone)  to shut off the water on that head(s) TOTALLY. This increased pressure may be enough to cause the small leak to burst. Continue to walk the sprinkler zone looking for mushy ground and water pools.  Also, go look at your water meter for measured water usage.  Look for the meter to be moving at a medium to  rapid pace (make sure everything in the house is turned off). TIP: Since lawn sprinkler heads are not rated to hold full pressure like a faucet, some small degree of water oozing is acceptable.
  2. If you have other styles of heads or #1 didn’t find it, this step #2 will be dirty wet work.  Conceptually, it’s the same as #1 but requires you to expose each and every head on the zone and install a threaded cap to replace each sprinkler. In this method, you have  to remove all the heads from the equation and the zone should hold pressure just like any pressurized plumbing line. Check the water meter; if you still see a water loss, leave the zone on for 2 or 3 hours, or even the whole day. Again, look for water pools or mushy ground and check your meter.

You may also find benefit in reading the other articles I have written on the subject: Lawn Sprinkler Efficiency Part II, Lawn Sprinkler Efficiency Part I ,  Searching for Lawn Sprinkler Valves, Chasing Lawn Sprinkler Leaks

4 Responses to Finding Leaks in Sprinkler Zones and Common Problems

  1. mrsmove says:

    Hi,
    This is a great piece of information, Thanks.
    I Have a problem of a different sort and that is ONLY part of one of my zones works but not the other. The problem started when I realized that after each time the grass cutters leave I have a sprinkler head problem somewhere. I recently realized that there is a dry area in the back of my yard, so I started looking for the problem. I realized that most of the sprinkler heads in that area are damaged, either they wont come up or they are broken. I started replacing them. Howeve, while doing so I realized that there are some sprinkler heads that I know they existed are not visible nor can be found. I looked hard but to no avail. and the fact that my soil is clayish, when it is dry it is so hard to dig . I am thinking that grass or soil covered them completely. I followed the possible logical line of sprinkler series only to get more frustrated… Now, after fixing the heads that i can see, I am left with one part of one zone or two parts of two zones that are not functional. Could a bad solinoid do that ? I tried all 4 zones and all zones work, but some parts of a zone or zones do not. this is strange… can a clog of one head prohibit the rest of heads from working? Or what do you think the problem is????
    Please help

    • homeownerbob says:

      By design, the zone is not under pressure when it is not running. In turn, when the water is shut off on the zone, the section will naturally bleed down by pushing out water at the lowest (elevation) head and sucking in air from the others. Any of the heads that were damaged are suspect for drawing in dirt and debris. My belief is that you may have a blocked passage in one of the pipes. To get enough pressure in the system to unblock it, you will need to close or cap all the heads that currently spray water (in the effected zone). This should generate enough pressure to blow the gunk out. However, you need to pull either the nozzles or entire heads of the non-working heads to let the gunk get out. Here is the tricky part; just like a broken head, when you cut the water off to replace the nozzles/heads, they will suck the dirty water back into the pipe. So you will need a helper to replace the nozzle while there is still some positive pressure or the nozzle stem needs to stay erect once the pressure is released. I have used a pair of vise grips with a very weak grip, just enough to hold it up, but not crack the plastic, that way it will just suck air until you get there to replace the nozzle. Hopefully this will work, otherwise its starts getting really ugly from this point on. So let me know and I can give you some next step procedures. BOB

      • mrsmove says:

        Thanks a lot for the information. Actually, I was able to “find” ALL sprinkler heads this morning. And since most of my sprinklers were next to the border walls, They were so grossly covered by vine roots. The vines were spreading on the walls and there roots were covering the heads slowly but surely until they overcame most. And because my “Amigos” do give a rats sh*#* they let the superficial roots creep insted of edging properly because its easier for them … Then to complete there “mission” they ran over the heads with riding mowere over the heads, either causing them to sink farther or just braking them… Any way I fired the he## out of them and did the following … I hope this will be helpful to others. I had VERY hard time finding the innitial 2 heads in a raw then when I did I measured the distance between them then started applying the distance onward to estimate approximate area of the next head(surely another “amigo” installed the system and did not care to be accurate, but within 2-4 feet of the area) and so on so forth…. Untill I found all of them by softening the roots with the rake and trimmer then blowing compressed air on the area until i see a clue. Actually one of the heads took me more than all others combined… But I knew it was in the area because I serviced it last year when I first moved in. (I dug one foot deep and 10′x1′ wide to find that head ) WHen I found it i opened all heads. I cleaned some and replaced most and lifted others. Now I had all my sprinkler heads open only from the top. I tried the system to see if water will be present “somewhere” , still all the ones working before were working and all others in the same zone, and one other zone, were not. At least I got all the head exposed now, AND, so, I got my air compressor and started pumping air in the ones not working. I was so happy to see that every one I tested was pumping out whatever water was there or I put there through the other one. So on, untill I confirmed that there is no blockage or leak. Put the inserts back and started the system. Nothing,… Shock…the zones that were not working are still not working. I went back to the solenoid, and eventhough the voltage was there and the nock noise was there, i thought of changing it, maybe something mechanical not electrical, I thought… Nothing … However when I took off the solenoid the partial zone that was not working worked perfectly this time… that was a GREAT relief… Now I still have no water running when I turn the system on, but at least I know there is no blockage nor leak. I will take off the valve chamber, clean it and maybe replace the membrain. Any idea?
        Thank you for your nice and appreciated concern.

      • homeownerbob says:

        Sounds like good news! You definitely had one of those extreme cases. I didn’t think of the compressed air solution as many homeowners may not have access to that tool, but as you figured, it worked! There is a chance that you may still have some floating blockage. Once you clean the valve, close all the nozzles except the last head. Pull the nozzle and filter from that head. That should drive all the remaining dirt out of that head. Let it run for about 5 seconds. You may still need to go back and clean the filters at each nozzle to get the fine dirt out. Good luck and keep plugging. BOB

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