Capping a sprinkler head is a common process in irrigation maintenance, often necessitated by changes in landscaping or the removal of a broken unit. This modification redirects water flow within the lateral line, preventing spraying at the unwanted location. Removing a sprinkler head and sealing the line is a practical DIY task that ensures water conservation and maintains necessary pressure for the remaining active heads in the system.
Essential Tools and Safety Preparation
Before commencing any work, locate and shut off the water supply to the irrigation system or the specific zone you plan to work on. Failure to depressurize the line risks a sudden spray of water once the existing head is removed. Once the water is off, run the system briefly to relieve any residual pressure in the pipes, confirming the line is safely deactivated.
You will need a small trowel or shovel for excavation and a rag to clean the exposed components. The replacement seal will be a threaded female cap, often PVC, or a brand-specific blanking adapter that matches the riser’s thread size, typically one-half or three-quarter inch. A roll of Teflon tape is necessary to create a watertight seal on the threads.
Step-by-Step Instructions for Capping the Riser
Begin by carefully excavating the soil around the sprinkler head you intend to remove, using the trowel to avoid damaging the underground piping. Dig down until the connection point between the sprinkler head and the threaded riser is fully exposed, which is usually about five to six inches deep. Once uncovered, twist the existing sprinkler head counter-clockwise to unscrew and remove it completely from the riser.
With the sprinkler head gone, gently clean the exposed male threads of the riser pipe to remove any dirt or grit that could compromise the final seal. Wrap the Teflon tape clockwise around the riser threads, ensuring the tape follows the direction of the threads so it does not unravel when the new cap is installed. Applying three to five wraps of tape provides a consistent, pressure-resistant layer for sealing.
Next, take the threaded female cap and align it carefully onto the wrapped riser, turning it clockwise by hand. Hand-tighten the cap securely without using tools that could overtighten and crack the PVC riser or the new cap itself. After the cap is installed, slowly turn the zone water supply back on for a brief moment to check the connection for any leaks or drips. If the seal holds without issue, the water can be turned off again, and you can backfill the hole with the excavated soil.
Addressing Temporary Plugs and Line Termination
For situations requiring a very short-term fix, such as immediate leak stoppage or temporary winterization, a rubber plug or a brand-specific shut-off nozzle can be used. These temporary solutions seal the water flow at the point of the head but are not designed for long-term, high-pressure conditions.
A more permanent solution is required when the entire feeder line, known as the lateral line, must be terminated deep underground. This involves digging down to the lateral pipe and cutting the pipe just past the tee fitting that feeds the sprinkler riser. A slip cap must then be installed over the cut end of the lateral pipe using PVC primer and cement, which solvent-welds the cap to the pipe. This method creates a permanent, non-threaded seal below the grade, effectively removing the entire branch from the system.