Spring Sprinkler System Startup

Before turning on the water, inspect your entire system visually. Walk each zone and check all sprinkler heads for damage—freeze-thaw cycles can crack plastic heads. Remove dirt or debris that accumulated over winter. Look for missing heads or broken risers. Check the backflow preventer (the brass assembly above ground near the foundation). If it was not wrapped for winter, inspect for frost cracks. Check the controller (timer): replace the backup battery, verify the time and date are correct, and review your zone schedules. Clean or replace the controller filter if your system has one. Locate the main shutoff valve and the vacuum breaker. Plan to replace any damaged components before startup. Having spare heads and risers on hand makes repairs immediate.

Open the main water supply valve slowly—¼ turn at a time with pauses—to let air escape gradually. Close the test cocks on the backflow preventer and position the valves at 45 degrees. Turn on the controller to each zone manually but keep the zone valves closed. Open the zone valve for the first zone fully, then open the corresponding test cock on the backflow preventer to vent air. Once water flows steadily from the test cock, close it. The zone should now be pressurized. Run the zone for 2 minutes to flush debris from the lines. Then move to the next zone. After all zones have been flushed, set the controller to automatic mode with your desired schedule. Run each zone again for full cycle to verify coverage and check for leaks.

The backflow preventer is a critical safety device that keeps irrigation water from contaminating your drinking water supply. Spring startup requires testing or replacing seals in the backflow preventer. Inspect the rubber seals and gaskets on the test cocks and relief valve. If they are cracked or stiff, replace them. The relief valve should drip slightly during startup as air bleeds—if it streams continuously, the internal check valve may be stuck open and needs service. Pressure test the backflow preventer by running a zone and checking that the relief valve does not open under pressure. Many municipalities require annual backflow testing by a certified tester. Schedule this with a professional if required in your area.

After startup, run each zone individually for 5–10 minutes. Walk the zone and look for: heads that do not pop up fully (clean or replace), heads spraying in wrong direction (rotate the body), misting instead of droplets (pressure too high—install pressure regulator), pooling water (broken pipe or low head drainage), dry spots (add a head or adjust existing coverage). Check that each head covers adjacent heads with overlap (head-to-head coverage). Adjust spray arcs to avoid watering hard surfaces. For rotor heads, adjust the radius screw to avoid overspray onto buildings or sidewalks. Verify the controller schedule matches your local watering restrictions. Set run times for each zone based on soil type and sun exposure.