How to Repair a Sprinkler System: 7 Ways

How to Clean Sprinkler Heads

The signs of a clogged sprinkler head are patches of brown grass around the sprinkler head or a sprinkler head that will not rise or only partially rise. Dirt and fine sand will clog the filter in the pop-up section of the sprinkler head. 

Sprinkler filters are small, mesh plastic devices that drop into the top of the pop-up. Filters cost about $1 or less.

Cleaning or replacing the filter in the sprinkler head will restore the uniform spray pattern and allow the sprinkler heads to rise. You will need a spring clamp or locking pliers, needle-nose pliers, a bucket, mild soap, and an old toothbrush.

1. Lift Sprinkler Pop-Up

   Lift the sprinkler pop-up section by hand to its highest position.

2. Access the Filter

   Unscrew the top threaded section of the pop-up to access the filter.

3. Remove the Filter

   Remove the filter. Use needle-nose pliers if necessary.

4. Clean the Filter

   Clean or replace the filter. To clean the filter, use a toothbrush, soapy water, and clean water to rinse.
   

5. Flush Out the Sprinkler

   Turn on the sprinkler system before replacing the filter to flush out the system.
   

6. Replace the Filter

   Replace the filter and screw the threaded section back into place.
   

7. Unclamp the Riser

   Unclamp the riser to let the sprinkler head fall back into place.

How to Replace Sprinkler Heads

Signs that it is time to replace a sprinkler head are when grass around the sprinkler is discolored or patchy, the sprinkler head does not rise or only partially rises, or when the sprinkler head has become damaged.

A sprinkler head has a large plastic cylindrical base that connects to the water line and a top telescoping cylinder that rises to spray water. The pieces are unified. So, even if just the top part is damaged, the whole sprinkler head unit must be replaced. 

Sprinkler heads cost from $5 to $35 each. Purchase a sprinkler head that is specific to your system. Most sprinklers have a pop-up gear-driver rotary head or a pop-up fixed head. Sprinklers have either 1/2-inch or 3/4-inch inlets. Half-inch is common with pop-up fixed sprinkler heads.

1. Cut Around the Sprinkler Head

   Use a garden spade to cut out a wide circle around the sprinkler head. Cut the turf carefully to avoid slicing buried sprinkler lines.

2. Unscrew the Sprinkler Head

   Unscrew the sprinkler head by hand until it releases.
   

3. Remove the Sprinkler Head

   Gently lift the sprinkler head out of the hole.
   

4. Insert New Sprinkler Head

   Place the new sprinkler head into the hole and onto the male thread at the base.
   

5. Tighten the Sprinkler Head

   Hand-tighten the sprinkler header until it is firmly in place. Do not over-tighten.

How to Replace Damaged Sprinkler Risers 

Signs of a damaged sprinkler riser are overly wet patches of grass or mud or excess grass growth directly around the sprinkler head. 

A sprinkler riser is a 1/2 inch or 3/4 inch diameter PVC pipe that extends from the top of the sprinkler pipe to the bottom of the sprinkler head.

Sprinkler risers come in lengths from 1/2 inch to 24 inches. Cut-off risers are a good option when you're not sure of the riser's exact length. Cut-off risers have six to eight segments that can be easily snapped off to adjust the length of the riser. A 1/2-inch by 12-inch cut-off riser is a versatile length and costs $1 to $2 each.

1. Remove the Body

   Remove the sprinkler head body.

2. Grasp the Riser

   Reach into the hole vacated by the sprinkler head and grasp the riser.

3. Turn the Riser

   Turn the riser counterclockwise.
   

4. Cut to Size

   Measure the new sprinkler riser against the old riser and cut it to size with a PVC pipe-cutting tool.
   

5. Tighten the Riser

   Place the end of the riser in the hole and tighten it by hand.

How to Repair Low Water Pressure 

Signs of low water pressure in a sprinkler system are brown circles around sprinkler heads, non-uniform spray patterns, and sprinkler heads that fail to rise.

1. Clean the Sprinkler Head

   Clean the sprinkler head and filter or replace the filter if the low water pressure is localized at just one or two sprinklers. Or replace the entire sprinkler head if cleaning the old sprinkler's filter doesn't improve the water pressure.

2. Run Sprinklers

   Run the sprinklers during non-peak water use hours. Peak hours are generally from 9:00 am to 5:00 pm, though every area is different.
   

3. Open the Isolation Valve

   Open the isolation valve all the way. The isolation valve is in the covered valve box. A knife valve handle should be parallel to the pipe and a round handle valve should be turned completely leftward.
   

4. Open the Main Water Shut-Off Valve

   Open the house's main water shut-off valve all the way. Water for sprinklers comes from the curb-side water meter, goes into the house through the water shut-off valve, and is once again sent outside to the sprinklers. Make sure that the water shut-off valve is opened to full.

How to Replace Leaking or Damaged Sprinkler Pipes 

The signs of leaking or damaged sprinkler pipes are muddy, soggy patches located anywhere in the lawn or patches of lawn that are higher or greener than other areas.

A telescopic repair coupling lets you cut into the broken line, shorten the coupling in order to place it on the line, then length it again permanently.

1. Dig a Trench

   Dig a trench around the suspected line break.

2. Turn off the Water

   Turn off the water to the sprinkler system.
   

3. Add Cut Marks

   Add the cut marks to the PVC sprinkler line. One mark should be on the inside edge of the slip coupling and the other mark should be at the end of the telescope base.
   

4. Cut the Line

   Cut the sprinkler line on the marks with the PVC cutter.
   

5. Clean the Pipe

   Clean the pipe of all dirt.
   

6. Collapse the Coupling

   Collapse the repair coupling to its shortest length.
   

7. Apply PVC Solvent

   Add PVC solvent to the ends of the cut pipe and to the inside ends of the coupling.
   

8. Extend the Coupling

   Working quickly, place the coupling between the cut pipe and extend the coupling.

   Tip

   Be sure to hold the coupling extended for about a minute for the solvent to fully cure.

How to Diagnose Voltage or Transformer Issues 

Signs that the sprinkler system is experiencing voltage or transformer problems are when individual sprinkler zones will not turn on or when the entire system does not turn on.

The issue may be with the sprinkler controller or with the field wiring. You will need a multimeter, flashlight, and 0.75 amp replacement fuses.

1. Check the Controller

   Make sure that the controller is programmed correctly.

2. Check the Power

   If none of the sprinkler zones will run, check the power source that feeds that sprinkler system's transformer.
   

3. Check the Wires

   Examine the wires on the transformer to ensure that all are properly attached to the terminals.
   

4. Test for Voltage

   If some zone are working and others are not, use the multimeter to test for the correct voltage to the non-working stations. Most residential sprinkler systems are 24V systems which should output a signal in the 24V to 28V range.
   

5. Check for Wiring Problems

   If the controller is sending the proper current to the non-working stations, check the continuity of the circuit to identify any wiring problems.
   

6. Replace the Fuse

   If the controller has a fuse, the fuse may be blown. Remove the fuse and replace it with a fresh fuse.

How to Replace Faulty Sprinkler Solenoids

One sign of a faulty sprinkler solenoid is when an individual sprinkler valve will not turn on even if the rest of the electrical system is working properly. You'll know if an individual sprinkler solenoid is faulty if three conditions are present: it has worked before, other valves are working, and the main controller is working.

A sprinkler solenoid is an electric device that tells a sprinkler valve to open or close based on commands from the system's main controller. A sprinkler solenoid costs from $15 to $35.

1. Turn Off the Water

   Turn off the water to the sprinkler system.

2. Locate the Solenoid

   Locate the sprinkler solenoid in the covered valve box.
   

3. Locate the Wires

   Locate the wires that connect the main controller to the solenoid. The bundled wires will the connected with a plastic wire nut.
   

4. Untwist the Wires

   Screw the wire nut off of the bundle and untwist the wires.
   

5. Remove the Solenoid

   Remove the old solenoid by turning it counterclockwise.
   

6. Replace the Solenoid

   Install the new solenoid by turning it clockwise by hand.
   

7. Connect the Solenoid

   Connect the solenoid's white wire to the system's white wire with a wire nut.
   

   Connect the other solenoid wire to the system's power wire, which may be red or black.

8. Test the Sprinkler

   Turn on the sprinkler system and test it.