A home irrigation system delivers water efficiently to a landscape, automating the watering schedule to ensure plants receive the correct volume of moisture. Constructing a customized system allows the homeowner to optimize water usage based on the unique needs of their property. This calculated application of resources replaces haphazard watering, leading to healthier plants and potentially lower utility bills.
System Planning and Design Fundamentals
The initial phase involves a detailed assessment of the existing water supply and the landscape layout. Determine the available water flow rate (GPM) and the static pressure (PSI) at the main connection point. A simple bucket test, where a five-gallon bucket is timed as it fills, combined with a screw-on pressure gauge, provides the necessary data to size the system correctly. These measurements establish the maximum capacity of any single irrigation zone.
Next, the landscape must be divided into distinct hydrozones, which group plants with similar water requirements. For example, a sunny lawn demanding frequent, shallow watering should be separate from a shaded perennial bed requiring less frequent, deeper saturation. Designing the system around these zones maximizes efficiency and plant health by preventing overwatering of drought-tolerant species. Each zone must use a single type of emission device to maintain a uniform precipitation rate.
The calculated GPM and PSI dictate the number and type of emission devices that can operate simultaneously within a single zone. For instance, if the available flow is 12 GPM, a zone cannot exceed this volume when running. Selecting between a broadcast sprinkler system (suitable for large turf areas) and a targeted drip system (better for garden beds) depends on the hydrozone’s needs. Drawing a precise blueprint mapping the zones, pipe routes, and device locations is necessary before purchasing materials.
Essential Components and Sourcing
The foundation of a reliable irrigation system is selecting durable and compatible components, starting with the main supply line. Polyethylene pipe is often preferred for its flexibility in residential applications. Rigid PVC is sometimes used for main lines due to its higher pressure rating and ability to be buried in deep trenches. The pipe diameter, typically ranging from three-quarters of an inch to one inch, must be chosen based on flow calculations to minimize friction loss.
A mandated component is the backflow prevention device, which safeguards the potable water supply by preventing contaminated irrigation water from flowing backward. Common residential options include the Pressure Vacuum Breaker (PVB) or the Double Check Valve Assembly (DCVA), depending on local plumbing codes. If using a PVB, it must be installed at least 12 inches higher than the highest sprinkler head.
Following the backflow device, the system requires a manifold assembly where solenoid valves are grouped, with one valve corresponding to each hydrozone. These valves are electrically activated by a central controller, regulating when water flows into the lateral lines of each zone. The final components are the emission devices, such as rotary nozzles for turf or pressure-compensating drip emitters for garden beds. These are selected to match the desired precipitation rate for the specific hydrozone. Sourcing materials often involves specialized irrigation suppliers and local hardware stores.
Step-by-Step Installation Process
Installation begins immediately after the main water connection point and the backflow prevention device. The first physical step is trenching, which requires laying out the pipe paths according to the design plan, marking them clearly. Residential sprinkler lines are typically buried between 8 and 12 inches deep to protect them from surface damage and temperature fluctuations.
Using a shovel or a rented trenching machine, the trenches should be dug to a uniform depth. Ensure any buried wiring for the solenoid valves is run in a separate trench or at a different depth from the water lines. The main supply line is laid first, connecting the water source to the location of the valve manifold. Connections for PVC pipe are made using primer and solvent cement, while polyethylene pipe utilizes barbed fittings and clamps.
Assemble the valve manifold next, connecting the main supply line to the individual solenoid valves. The lateral lines, which branch out from the valves to the emission devices, are then run down the pre-dug trenches. Using different pipe diameters for the main line and the lateral lines helps maintain optimal water pressure throughout the system.
Before attaching the final emission devices, the system must be thoroughly flushed to clear any debris or shavings that entered the pipes during construction. Run water through each zone for a short time before sealing the ends or attaching the devices. Sprinkler heads are typically installed using cut-off risers that allow them to pop up when active and retract when the system is off.
Once all connections are secure and the emission devices are in place, carefully backfill the trenches with the excavated soil. Lightly compacting the soil helps prevent future settling around the pipes. After backfilling, the system is ready for the initial pressure test and programming.
System Activation, Programming, and Optimization
Slowly activate the water supply to pressurize the main line and check for immediate leaks at the manifold and fittings. Manually run the cycle on the controller to visually inspect each zone for major breaks or spurting joints. Minor leaks can often be tightened, but significant failures require opening the trench for component replacement.
Programming the controller requires inputting the start times and run times for each hydrozone. These times are determined by the landscape’s water needs and the calculated precipitation rate of the emission devices. Adjusting the sprinkler heads ensures proper coverage and minimal overspray onto sidewalks or driveways, preventing water waste.
Finally, the system’s performance must be verified through a systematic check known as a “catch can test,” which assesses the uniformity of water distribution. This test involves placing several identical, straight-sided containers randomly throughout a zone and running the system for a set period. Measuring the depth of water collected in each container allows calculation of the average precipitation rate, and inconsistencies in coverage can be identified. If the water depths vary significantly, adjust the sprinkler head spacing or type to achieve a more uniform application.