Mending Drip Irrigation Tubes

Ever cut through a drip irrigation line?  I have and it is not a good feeling.

There are few disconcerting, even sickening, feelings than to be shoveling merrily away in the garden and suddenly feel that distinctive “crunch” when you cut through a drip irrigation line.  When this happens you have three choices: 1) give up on gardening completely, walk away from the site of destruction, and find another hobby; 2) call someone to come fix the line, or 3) get out the tools and supplies and repair the damage.  Most of us, after having gone through the “Oh, no!  What have I just done!” stage, select number three and get it done.

Even if you are one of the lucky ones and have never sliced through a drip line, it is still a good idea to regularly make sure that all is working properly and, if not, conduct regular maintenance.  Because plants depend upon the irrigation system for life-giving water, the overall success and health of our plants is dependent upon how well the system functions.  Good maintenance is a key to garden and landscape success. Finding plugged emitters, broken lines, or clogged filters during the heat of summer is no fun, and regular maintenance during cooler weather will often prevent these mid-summer hassles.  Still, accidents happen and damage occurs.  With plastic drip irrigation systems, repairs are usually fairly simple. 

First, locate the exact site of the problem. If the tubes are underground, a sure fire test for cuts or tears in the delivery system is to look for water soaked areas on the surface of the soil.  Water escaping from a line under pressure will soak through to the soil surface and create a boggy area that is much more moist than other areas around it.  Excavate the irrigation line by digging carefully down to the tube and search for a cut or slice.  If you have an above ground system, look for geysers spraying into the air.

Once you have found the exact site, you next have to decide how best to repair it.  For simple slices or nicks, couplers are the best way to go.  To save time traveling back and forth to the store for the correct parts, it is a good idea to plan the repair job first and then assemble a parts list.  This is also the time to decide on what tools you will need.  Hunt them all up and have them ready to hand before starting the project. 

The biggest challenge to quick and easy repairs is to have the correct-sized parts on hand.  It does no good to have a three-eighths coupler to fit a half-inch line.  It just won’t work.  However, most drip tubing is of a uniform size which makes it easy to find the right parts.  It is always a good idea to double check everything before getting down on elbows and knees in the mud to do the actual repairs.

Once you have all the parts together, it is time to start the job.  At the point where the damage has occurred, use a sharp knife or small hand saw to make a straight up and down cut through the tubing.  This will make sure that all of the fittings will match evenly and seal tightly.  A cut that is uneven will leave a side with less plastic to plastic contact resulting in locations where leaks may occur.

Just about any plastic tubing can be easily repaired with slide on, or in, couplings that join the two ends of the tube in a water-tight fitting.  These couplings are available at any hardware or garden store that services drip irrigation systems. 

The barb coupling has concentric ridges on the outside and around each end of the coupling.  The barb coupling slides into the plastic tubing as far as the coupling will allow.  The barbs grasp the inside of the tube to provide the necessary tight fit.

A compression coupler is different in that it slides over the top of the plastic tubing.  Both compression and barb couplers take a little work to move them into the right position for a strong, water-tight fit.

Those who are experienced in making repairs generally agree that the compression coupler is the better way to go.  Even though they are almost double in cost over the inside-the-tube barb couplers, they seem to have a better track record of success.  This is probably due to the water pressure inside the tube.  As pressure builds, the tube expands or swells in diameter slightly.  For compression couplers, the increased pressure pushes the tube  even tighter against the coupler, and thus, creates a tighter fit.  On the other hand, the pressure tends to loosen the connection between the inside-the-tube barb couplers.

If the damage is in thicker-walled PVC pipe, slide-on PVC couplers will work for small breaks, but extensive damage may require the replacement of sections of pipe.  Remember that PVC must be glued together with an approved adhesive.

Damage to above-ground feeder lines or emitters are fairly easy to repair.  Most systems are designed to add or remove emitters easily.  Holes created for emitters or spaghetti tubing can be plugged by snapping in “goof plugs,” attachments that are designed to correct mistakes in the assembly process.

Sometimes drip system filters will become plugged with precipitated salts, algae, or sand.  Most filters can be removed and rinsed to ensure good service.  If the screen inside the filter is damaged, replace it. The filter is a critical part of the system and scrimping and “making do” can cause you many headaches down the road.

All drip irrigation systems need to be flushed out regularly to get rid of accumulated contaminants that might collect at the end of the tube.  At the end of each line, there should be an access point which can be opened to allow the water to flow freely.  Once opened, the water pressure should push out any contaminants that might be inside.

With a little know-how and some time, your labor-saving system can be back up and running just like new, that is, until you cut it again.

If you have questions, you can reach one of the Master Gardeners at the Cooperative Extension office, 820 E. Cottonwood Lane, Building C, in Casa Grande.  The telephone is (520) 836-5221, extensioin 204.  The author’s email address is gibsonrd@ag.arizona.edu.

The University of Arizona is an equal opportunity, affirmative action institution.  The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Rick Gibson
Extension Agent, Agriculture
University of Arizona Cooperative Extension
820 E. Cottonwood Lane, Building C
Casa Grande, Arizona 85122
Voice:    (520) 836-5221
Fax:    (520) 836-1750
email:    gibsonrd@ag.arizona.edu