Bringing an in-ground sprinkler system back online for the season requires a deliberate, step-by-step approach. This process is typically performed in the spring after the danger of freezing temperatures has passed and involves carefully reintroducing water pressure to the system. Rushing this procedure can easily lead to significant damage to components like pipes, valves, and the backflow prevention device. Understanding the sequence of actions ensures a smooth transition to summer watering.
Initial System Inspection and Preparation
Before any water is introduced, inspect the entire system for signs of damage sustained over the winter months. Locate all manual drain valves used to empty the lines for winterization, ensuring they are fully closed to prevent immediate water loss.
If an air compressor was used during the winterization process, the specialized air plug or connector must be removed from the system’s main line. Simultaneously, conduct a visual inspection of all sprinkler heads to check for physical damage. Look for broken risers or tilted heads that may have been hit by equipment or displaced by ground shifting.
Confirm the main water shut-off valve, which controls the water flow from the source to the irrigation system, is in the fully closed position. This interior valve is often located in a basement, crawlspace, or utility room. Keeping this valve closed initially provides complete control over the rate at which water is introduced into the empty pipes.
Safely Restoring Main Water Pressure
The process of repressurization begins with the main interior shut-off valve, which should be opened with extreme caution and slowness. Start by turning the valve handle only about one-quarter of a full rotation. Introducing water too quickly into empty pipes creates water hammer, which generates pressure waves that can rupture seals and fittings.
After the initial quarter-turn, listen carefully for the sound of water beginning to fill the main irrigation lines. Allow several minutes for the initial rush of air and water to stabilize within the pipes. This slow introduction allows air pockets to compress and escape, preventing excessive pressure buildup.
The next focus is the backflow prevention device (BPD) or pressure vacuum breaker (PVB), which prevents irrigation water from contaminating the potable water supply. Before opening the main valves on this device, confirm that the small test cocks are completely closed. These cocks are used by certified inspectors for system testing.
The backflow device typically has two main isolation valves. Slowly open the valve closest to the water source—the inlet valve—using the quarter-turn technique. Water will begin to fill the device itself and the remaining pipes leading to the zone valves.
As the water fills the backflow device, a small spurt of water may briefly exit the atmospheric vent, which is a normal function designed to relieve pressure. Once the water flow appears stable, wait a few minutes for the pressure to equalize throughout the device.
Finally, the second isolation valve on the backflow device—the outlet valve—can be opened. This valve should also be opened very slowly, using the same quarter-turn method, allowing pressure to gradually build up in the rest of the irrigation piping network. Once both BPD valves are open, the interior shut-off valve can be fully opened to ensure maximum flow.
Testing Zones and Setting the Controller
With the main lines fully pressurized, attention shifts to the electrical control unit, which should now be plugged in or have its power restored. The controller sends low-voltage electrical signals to the solenoid valves in the yard, telling them when to open and close.
Initiate a manual test cycle on the controller, programming it to run each zone sequentially for a short duration, perhaps one or two minutes. This test activates the solenoid valves one by one, allowing water to flow to the specific section of the landscape. Activating zones manually also confirms the functionality of the low-voltage wiring.
While each zone runs, walk the area to observe the performance of the sprinkler heads. Check that the heads are fully extending and retracting cleanly, and that the spray pattern provides uniform coverage across the designated area. Any heads that are not spraying or are weeping excessively indicate a potential issue.
This is the time to make minor adjustments to the arc and distance of the spray patterns using the appropriate adjustment tool. Ensure the water is landing on the lawn or plants and not spraying onto walkways, driveways, or the house structure. Improper aiming can lead to wasted water.
Once the physical check is complete, the controller needs to be programmed for the season’s watering schedule. Set the start times, the run duration for each zone based on soil type and plant needs, and the specific days of the week the system should operate. Modern controllers often use local weather data to optimize these settings automatically.
Addressing Common Startup Issues
It is common to find minor weeping or small leaks around the backflow device or valve boxes during the initial pressure test. Often, small leaks near threaded connections can be resolved by simply tightening the fitting slightly. Sometimes, cycling the water on and off a few times can help reseat internal seals within the valves.
If a specific zone fails to turn on during the manual test, the issue is typically electrical or related to the valve solenoid. Check the wiring connections at the controller terminal box and then at the valve box in the yard to ensure the wire nuts are secured and the low-voltage current is reaching the solenoid. A multimeter can be used to check for the required 24-volt AC signal.
Loud banging or shuddering noises, indicative of water hammer, mean the main water valve was opened too quickly. To mitigate this, fully close the main interior valve and then re-open it even more slowly than before, taking five to ten minutes to reach the full open position.
Any sprinkler heads found to be visibly cracked, consistently leaking from the base, or failing to pop up must be replaced immediately. Allowing a broken head to run wastes significant amounts of water and dramatically reduces the pressure available to all other heads in that zone. Replacing heads promptly maintains the designed hydraulic balance of the system.