Winterizing your sprinklers in Ogden

Why it matters

Water expands as it freezes: about 11 cubic feet of water becomes 12 cubic feet of ice. In a sprinkler system that expansion bursts pipes and fittings and cracks valves, sprinkler heads and backflow assemblies. Ogden averages about 121 nights a year at or below freezing, so a system left full over winter is a repair bill waiting for spring. Colorado State University Extension's point is simple: it costs far less to prepare a system in fall than to fix the damage.

When to do it

USU Extension lists blowing out irrigation systems as an October and November job in northern Utah. If you're on secondary water, Weber Basin usually stops deliveries around October 15, subject to supply, and asks that systems be drained for winter with valves shut before spring start-up. Aim to finish before the first hard freeze rather than after it.

The steps

USU Extension's sequence:

1. Turn off the irrigation water at the main supply to the system.
2. Release the pressure by turning on each zone's valve.
3. Open the drain valves, if your system has them.
4. No drain valves? Use an air compressor to push the water out of the lines.

Blowing out with air: keep the pressure down

USU doesn't give a pressure limit. Colorado State University Extension does: 40 to 80 psi, with 80 psi the maximum for rigid PVC and 50 psi for polyethylene pipe. Higher pressure can damage the very pipes you're protecting.

Don't use antifreeze

The American Red Cross says not to put antifreeze in sprinkler lines unless you've been directed to.

Protect the backflow device

The backflow preventer is often the most expensive part to replace, and it sits above ground where it freezes first. Colorado State University Extension's advice:

• Pressure vacuum breaker: open and close the ball valves and test cocks a few times, then leave them half-open for the winter.
• Reduced-pressure assembly: leave the isolation ball valves at about 45 degrees while draining and over winter.

In Ogden, culinary-water sprinkler systems need a backflow preventer, and pressure vacuum breakers and reduced-pressure assemblies must be tested every year by a certified tester. Spring start-up is a good time to book that test. See our landscaping page for Ogden's backflow rules.

Do it yourself, or hire it out?

Systems with drain valves are a straightforward DIY job. If yours needs a compressor, USU Extension suggests you may want an irrigation professional to blow it out; your local irrigation supply store can recommend someone. A pro brings a compressor that moves enough air at a controlled pressure, which a small home compressor often can't.

Vetted, locally owned landscapers who handle sprinkler work are listed on our landscaping page.

Don't forget the hose bibs

While you're outside: the Red Cross says to remove, drain and store hoses, close the inside valves that feed outdoor hose bibs, and open the outside bibs so they drain. More in our guide to preventing frozen pipes.

Sprinkler winterizing questions