Summer Irrigation System Startup & Outdoor Plumbing Guide

Why proper startup matters

Irrigation systems and outdoor plumbing sit unused for 4–6 months during winter. Rushing the startup — turning valves on too fast, skipping inspections, or ignoring winterization damage — leads to the three most expensive outdoor plumbing problems: burst pipes ($500–$2,000 to repair underground lines), cracked backflow preventers ($200–$600 to replace), and flooded zones that waste $50–$200/month in water and damage landscaping. A methodical 30-minute startup prevents all three.

Pre-startup inspection checklist

• Walk the entire system — before turning on water, visually inspect every sprinkler head, valve box, and pipe access point for winter damage: heaved ground, cracked fittings, animal burrow damage, or heads displaced by frost
• Check the backflow preventer — inspect for cracks in the body or bonnet (freeze damage is the #1 cause of backflow failure); test valves should move freely; if it was winterized with compressed air, all test cocks should be in the 45° position
• Inspect the controller — replace backup battery (annual task), verify the clock shows the correct time and date, check that zone wires are securely connected at the terminal strip
• Hose bibs and outdoor faucets — remove any winterization covers; turn on each faucet briefly while watching the interior shut-off valve area for leaks (frost cracks in the pipe behind the wall often only show when water pressure is applied)
• Check pressure regulator — if your system has one, verify it reads 40–65 PSI; too much pressure damages heads and fittings; too little causes poor coverage

Step-by-step startup procedure

• Open the main valve slowly — turn the irrigation main shut-off valve 1/4 turn at a time, waiting 30–60 seconds between turns; this prevents water hammer (pressure surges that crack pipes and fittings)
• Pressurize the backflow preventer — open supply-side shut-off valves slowly, then open test cocks from the 45° winterized position to the open position; check for leaks around the bonnet and test cocks
• Run each zone manually — at the controller, activate zone 1 for 2–3 minutes while walking the zone; watch for: geysers (broken heads, $3–$10 each), soggy spots (cracked lateral lines), zones that don't activate (faulty solenoid, $15–$30), and poor spray patterns (clogged nozzles — remove and rinse)
• Adjust head heights — pop-up heads should be flush with the ground when retracted and rise 3–4 inches when running; heads that have sunk below grade need riser extensions ($2–$5 each)
• Check for coverage gaps — run each zone during daylight and look for dry spots; adjust arc, radius, and nozzle size; head-to-head coverage (each head sprays to the next head) is the baseline for even watering
• Set the seasonal schedule — program watering for early morning (4–6 AM) when evaporation is minimal; most lawns need 1–1.5 inches per week; split into 2–3 cycles per zone to prevent runoff on slopes

Common startup problems and fixes

• Zone won't turn on — check wire connections at the valve box and controller; test the solenoid by manually turning the bleed screw 1/4 turn (water should flow); replace solenoid if it has a burnt smell ($15–$30)
• Low pressure on one zone — partially closed valve, clogged filter screen at the valve, or a leak downstream; open the valve box and check the filter; inspect for soggy areas indicating an underground leak
• Water hammer when zones switch — install a water hammer arrestor ($15–$40) near the manifold; this also reduces stress on pipe joints that cause long-term leaks
• Backflow preventer leaks — small seeps from test cocks may just need new O-rings ($5 DIY); continuous flow from the relief valve indicates failed internal check valves — call a certified backflow tester ($50–$100 for test and repair)
• Controller displays but zones don't run — check the common wire (usually white) at both the controller and each valve box; a broken common wire disables all zones

When to call a professional

Homeowners can handle head replacement, nozzle cleaning, schedule programming, and minor valve adjustments. Call a licensed irrigation specialist or plumber for: underground pipe repairs ($200–$500 per break), backflow preventer replacement or certification ($200–$600), adding new zones ($300–$800 per zone), pressure-related issues requiring regulator installation ($150–$300), or mainline leaks between the meter and the system. Most states require a licensed plumber for any work connected to the municipal water supply. Annual backflow testing ($50–$100) is legally required in most jurisdictions — check your local code.