Adding a sprinkler head to an existing irrigation line is a common home improvement task when seeking to extend coverage or address dry spots in the landscape. This process involves safely tapping into the main water-carrying pipe, known as the lateral line, to introduce a new water outlet. Successfully completing this project relies on careful preparation and precise execution of the steps for modifying the existing underground piping. This guide focuses on the practical, step-by-step procedure for physically installing the new connection.
Planning the Connection and Gathering Supplies
Before beginning excavation, accurately locate the existing lateral line by activating the specific irrigation zone and marking the pipe’s path with flags. Select and mark the exact spot for the new sprinkler head, ensuring it provides the desired coverage without overspray. Completely shut off the water supply to the entire system and relieve residual pressure by momentarily activating one of the zone valves before starting work.
You will need a set of materials and tools, including a shovel, pipe cutters, the appropriately sized T-fitting, and a flexible swing joint or riser. For PVC systems, acquire PVC primer and cement; for polyethylene (Poly) systems, ensure you have barbed fittings and hose clamps. Always verify that the new fittings and pipe material match the existing system to ensure compatibility and a reliable seal.
Cutting the Line and Installing the Tee Fitting
Carefully excavate around the marked location to expose enough pipe for cutting and fitting installation. Clear all soil and debris from the pipe surface. Measure the section of pipe to be removed; it must be exactly equal to the length of the new T-fitting that will be inserted.
Use specialized pipe cutters to make two clean, square cuts perpendicular to the pipe’s length, removing the measured section. Jagged or angled cuts compromise the seal and cause leaks. Immediately prevent soil or debris from falling into the open ends of the lateral line, as this material can clog the sprinkler head or valves downstream.
If working with PVC pipe, the connection relies on chemical welding. First, apply PVC primer to the outside of the pipe ends and the inside of the T-fitting sockets to soften the plastic. Next, quickly apply PVC cement to the same primed surfaces and immediately push the T-fitting onto the pipe ends. As you push the fitting on, give it a slight quarter-turn twist to evenly distribute the cement and ensure a watertight bond.
For polyethylene pipe, use a mechanical approach relying on barbed fittings secured with metal hose clamps. Slide a hose clamp over each cut end of the pipe before inserting the barbed T-fitting firmly into the pipe ends. Once the fitting is fully seated, tighten the hose clamps securely over the pipe and the barbs to create a pressure-holding seal. Allow the prescribed curing time for the cement or ensure the clamps are fully tightened before proceeding.
Attaching the Riser and Sprinkler Head
After installing the T-fitting, establish the vertical connection to the surface using a riser assembly. A flexible swing joint is the preferred method, as its multiple elbow connections provide shock absorption and allow for easy adjustment of the head’s position and height. This flexibility reduces the risk of damage if the head is struck by lawn equipment or shifting soil.
The riser connects to the upward-facing outlet of the T-fitting. Its length must be adjusted so the top of the sprinkler head sits flush with the finished grade. Ensuring the head is level with the ground surface prevents it from becoming a tripping hazard and allows lawnmowers to pass over it without obstruction. The sprinkler head is then threaded onto the top of the riser or swing joint assembly.
Before threading the sprinkler head, apply plumber’s thread seal tape (Teflon tape) or pipe dope to the male threads of the riser. This material acts as a lubricant and a sealant, filling microscopic gaps between the threads and ensuring a leak-proof connection. Thread the head on firmly by hand, then use a wrench to snug it down, taking care not to overtighten and crack the plastic housing.
Testing, Adjusting, and Burying the Line
Once the new connection is complete, slowly turn the main water supply back on to repressurize the irrigation system. Watch the newly installed T-fitting closely for any signs of leakage while the zone is activated. If water seeps from the joints, shut off the water, relieve the pressure, and repair the connection before continuing.
After confirming the connection is sound, allow the system to run to adjust the new sprinkler head’s spray pattern, arc, and distance. Use the adjustment screws or tabs on the head to fine-tune the spray so it covers the intended area evenly and prevents water from hitting sidewalks, driveways, or structures. Precise adjustment ensures efficient water use and maximum coverage.
The final action is to carefully backfill the excavated trench once the installation is leak-free and the spray pattern is optimized. Gently place the soil back into the trench, ensuring the pipe remains undisturbed and the swing joint is correctly oriented. Slightly compact the soil over the pipe to prevent settling, and consider marking the new head’s location for easier retrieval during future maintenance.