Winterizing a Sprinkler System in Freeze-Prone Climates: Drain Methods and What to Avoid

In Utah (and similar climates), proper winterization prevents costly freeze damage. The method depends on your system's layout.

Method 1: Gravity Drain (If System Has Slope)

1. Shut off the main irrigation supply valve (installed at the point of connection).
2. Manually open each zone valve (turn solenoid or bleed screw).
3. Go to the lowest head on each zone. Remove the head and its riser.
4. Water drains out. Replace riser and head.
5. Leave valves in manual-open position.
6. Insulate exposed valves, backflow preventer, and main supply with foam tape or insulation bags.

Method 2: Hand Pump (If Flat or No Drainage)

Use a small transfer pump (auto parts store fuel pump) with flexible tubing. Insert into each zone via a removed head or drain valve to pump out standing water.

Method 3: Leave Heads Off (Last Resort)

Remove several heads per zone and leave them off. Open pipes allow ice to expand lengthwise without bursting. Reinstall in spring.

What NOT to Do

Never add antifreeze, alcohol, or any chemical. It will contaminate the soil and plants on first spring startup. It's also illegal in many areas.

Best Practice: Blow-Out with Compressed Air

If you have access to a large-capacity compressor (10+ CFM at 50–80 psi), blowing out each zone is the gold standard. Many homeowners hire a pro for this ($75–$150). It's the most reliable method.