Reactivating a dormant residential irrigation system for the spring requires a careful, methodical approach to prevent costly damage to pipes and components. The primary objective is to allow the system to fill with water slowly, mitigating potential pressure surges that can rupture seals and fittings. Following a controlled procedure ensures the longevity of the system and prepares it for efficient operation throughout the growing season. This measured startup is especially important for the backflow prevention device, which is vulnerable to sudden changes in water pressure.
Initial System Inspection and Preparation
Before introducing any water, perform a thorough visual inspection of the entire system to identify any damage sustained during the winter months. Look closely at the above-ground components, checking for cracked or broken sprinkler heads or visible splits in the piping or backflow preventer assembly. Even with proper winter blowouts, cold conditions can cause fittings to fail or heads to shift due to soil movement.
Next, locate all manual drain valves and bleed-off valves that were opened for winterization and ensure they are fully closed. These valves are typically found near the main shut-off or at low points in the system’s mainline. Sealing all drain points prevents significant water loss and allows the system to build pressure correctly once the water supply is restored.
Gradually Reintroducing Water Pressure
Reintroducing water pressure is the most sensitive step, directly impacting the system’s integrity and preventing “water hammer.” Locate the main isolation valve for the irrigation system, often situated near the water meter or inside the home’s utility area. Slowly open this valve only about a quarter of the way, allowing water to trickle into the empty mainline.
Allow several minutes for the pipes to fill with water, listening for the sound of rushing water to subside as the air escapes through the system’s highest points. This slow filling minimizes the risk of a high-pressure wave traveling through the pipes, which could cause fittings to burst. Once the rushing sound stops, indicating the mainline is mostly charged, the main isolation valve can be slowly turned to its fully open position.
The backflow prevention device, such as a Pressure Vacuum Breaker (PVB) or Reduced Pressure Zone (RPZ) assembly, must be activated next. If the device was removed for the winter, reinstall it, ensuring the proper direction of water flow. Close all test cocks (small bleeder screws) on the device, which were likely left open for draining.
Slowly open the first main shut-off valve on the device and wait for the chamber to fill. Then, slowly open the second main shut-off valve, sometimes leaving it at a 45-degree angle initially to control the flow rate and prevent damage to internal components.
Testing Zones and Adjusting Sprinkler Heads
With the mainline fully pressurized, power on the control box and manually activate each zone to check for proper operation. Run each zone sequentially for a short duration, typically two to five minutes, to observe the function of the heads. Look for signs of water pooling or bubbling from the ground, which indicates a leak in the underground piping that requires immediate attention.
Observe the physical operation of each sprinkler head, confirming that they pop up fully and rotate or spray as expected. Clogged nozzles, often due to debris or sediment, can cause a distorted or weak spray pattern; these should be cleaned or replaced. Use a small flathead screwdriver to adjust the spray arc and distance, ensuring water is not wasted on pavement, sidewalks, or structures.
This physical inspection confirms that water is delivered uniformly across the intended landscape area. If a head fails to pop up or sprays an incorrect pattern, minor adjustments or cleaning the filter basket often resolves the issue. Any necessary repairs, such as replacing a cracked head or fixing a leak, should be noted and addressed before the system is set to run automatically.
Setting the Seasonal Watering Schedule
The final step is to program the irrigation controller with a schedule that accounts for the mild weather and lower plant water needs typical of early spring. Initial run times should be significantly shorter than summer settings, aligning with current soil moisture and evapotranspiration rates. Overwatering in the spring encourages shallow root growth and can lead to turf disease.
Consider implementing the “cycle and soak” method, particularly in areas with dense clay soil or on sloped terrain. This technique involves dividing the total required watering time into multiple shorter cycles, separated by a 30 to 60-minute rest period. This pause allows water to infiltrate the soil profile, preventing runoff and promoting deeper root development. Once programming is complete, ensure the controller is switched from the “Off” or “Manual” setting to “Auto” or “Run.” Also, confirm the functionality of the rain sensor, if installed, to ensure the system automatically shuts off during rainfall.