A homeowner can significantly enhance landscape management by installing a dedicated lawn sprinkler system. While the project involves careful planning and physical labor, a do-it-yourself approach is feasible. The effort invested results in a consistently greener lawn and reduces the time spent on manual watering. This permanent system manages water delivery efficiently, ensuring optimal hydration. The process starts with foundational design elements that determine the system’s performance.
System Planning and Layout Design
Successful sprinkler installation begins with assessing the home’s water supply to establish the system’s limits. The two important measurements are the static water pressure (PSI) and the flow rate (GPM). Static pressure is found by attaching a gauge to an outdoor faucet and taking a reading with all other water sources turned off.
Determining the flow rate involves the “bucket test,” measuring the time it takes to fill a container. GPM is calculated by dividing the container volume by the time in seconds, then multiplying by 60. These figures dictate the maximum amount of water available for any single zone.
The next step is calculating the number of watering zones needed. This is determined by dividing the total available GPM by the combined GPM requirement of the sprinkler heads in a potential zone. It is suggested to use only about 75% of the total measured GPM to account for pressure loss from friction. Planning the physical layout involves mapping the yard and dividing it into zones based on sun exposure, plant type, and the water consumption of the selected heads.
Two main types of sprinkler heads are commonly used: rotor heads and spray heads. Rotor heads use a higher GPM and are suited for large, open lawn areas, delivering water over a greater distance in a rotating stream. Spray heads use less water and are ideal for small, irregularly shaped areas or flower beds, providing a fixed fan of water. Proper selection ensures uniform water distribution, achieved by designing zones so the spray from one head reaches the head nearest to it, known as head-to-head coverage.
Preparing the Site and Laying Main Infrastructure
With the design finalized, the physical work begins by marking the trenches and component locations using spray paint or flags. Trenches must be dug to protect the main and lateral water lines from damage. While local codes vary, main lines, which are under constant pressure, are typically buried at a minimum depth of 10 to 12 inches. Lateral lines can be shallower, around 6 to 8 inches.
Connecting the system requires tapping into the main service line, often near the water meter. This involves cutting the existing pipe to insert a tee fitting, which is then solvent-welded in place. Immediately following this connection, a backflow prevention device must be installed to protect the potable water supply from contamination.
The backflow preventer, often a Pressure Vacuum Breaker (PVB) in residential systems, must be installed at least 12 inches above the highest sprinkler head to meet most plumbing codes. Following the backflow device, the main line runs to the valve manifold. The manifold serves as the central control point, consisting of individual zone valves connected to the main line that turn on and off based on signals from the system controller.
Installing Sprinkler Heads and Controller Wiring
From the valve manifold, the main line branches into smaller lateral lines running through the trenches to the sprinkler head locations. These lateral lines are only pressurized when their specific zone valve is open. Connections for the sprinkler heads are made along the lateral lines using tee fittings and flexible pipe, often called swing pipe. This flexible pipe allows for slight adjustments and absorbs impact to prevent breakage.
The sprinkler heads are screwed into risers or elbows at the end of the swing pipe. Ensure the top of the head is flush with the ground when retracted to avoid damage from mowing. The valve solenoids, which open and close the valves, require low-voltage wiring to connect them to the system controller. A multi-conductor cable, designed for direct burial, runs from the controller location to the valve manifold.
The wiring process involves connecting one wire from each solenoid to a common wire, shared by all zones. The other wire from each solenoid connects to its own designated zone wire. This low-voltage bundle connects to the controller’s terminal block: the common wire connects to the “C” terminal, and the zone wires connect to terminals labeled “1,” “2,” and so on. The controller is typically mounted in a dry, accessible location, such as a garage, and plugged into a standard electrical outlet.
Final System Testing and Seasonal Programming
Before the final nozzles are installed, the system must be flushed to prevent dirt or pipe shavings from clogging the heads. This is achieved by turning on each zone individually with temporary flush caps or no nozzles attached, allowing water to run for 15 to 20 seconds to clear debris. After flushing, the permanent nozzles are attached, and the system is ready for its initial hydrostatic test.
The testing phase involves activating each zone to check for leaks and observe the spray patterns and coverage. Sprinkler heads feature adjustable dials or set screws that allow the user to fine-tune the arc and the throw distance. Adjusting the heads ensures water is directed precisely onto the lawn and away from sidewalks or structures, minimizing waste.
Once the physical system operates correctly, the final step is programming the controller with an appropriate watering schedule. The schedule should be based on factors such as local climate, soil type, and the water needs of the plants in each zone. It is recommended to water in short, frequent cycles to allow water to soak in and reduce runoff, and to schedule watering for the early morning hours to minimize evaporation.