Why winterize your sprinkler system?

A very good question, indeed.  For a number of years, I worked as the Irrigation secretary here at Horizon, and one of my duties was to contact any of our customers at the end of the season who had not winterized their sprinkler systems.  I had a number of clients over the years who never winterized the sprinklers ever, and never had a problem.  These were the ones who would ask me what the point of winterizing was, besides giving us a reason to bill them for a service call.  They were also the ones who never had a clue just how fortunate they were.


It’s important to get all the excess water out of your sprinkler system before freezing temperatures hit.

To understand why a sprinkler system should be winterized (or blown out, or shut down, or however you have come to call it), you need to understand how a sprinkler system works.  Sprinkler systems consist of a controller, valves, wiring, sprinkler heads, connective plumbing and underground pipes.  When the system is active, the water flows from the house through the connective plumbing into the underground pipes and valves, and eventually comes out through the sprinkler heads.  Even when the system is turned off at the controller, water sits in the pipes, and also in the valves and heads, especially if they are at low points in the lawn, unless you blow it out with compressed air.  During a mild winter you could possibly get away with leaving the trapped water there, but once the ground freezes solid, it will freeze anything that is buried within it.  When water freezes, it expands, and when it uses up all the available air space, it will burst whatever contains it.

When the backflow device freezes

When the backflow device freezes………

Most at risk is the connective plumbing, which allows water from the street or your well to be diverted to feed the sprinkler system.  If installed properly, this feed has its own shut-off valve, and flows through a backflow preventer before moving into the underground pipes.  In most situations, the backflow device is on the outside of the house, above ground, and will have an exposed feed pipe that sends the water underground to the sprinkler pipes.  Because these parts are exposed, they are vulnerable to freezing temperatures and are usually the first thing to break.  If the break isn’t found right away and the sprinkler shut-off is still open, it can cause flooding against the foundation of your house.  (A bit of additional education – a backflow preventer keeps the irrigation water from reversing back into and contaminating the house water.  Backflow devices are required on all sprinkler systems in New Jersey, and should be tested yearly to safeguard the quality of your house water.)

The underground pipes, which are made of commercial grade plastic, are also at risk, especially on an older sprinkler system.  When a sprinkler system is first installed, ideally the pipes are laid 18″ below the surface, and are very well insulated until the ground freezes hard.  I say ideally because, especially in rocky Bergen County, NJ, sometimes it is impossible to get the pipes down that deep.  Even so, a newly installed system is very well protected into the late fall, and we really don’t have to think about the pipes much.  Out of sight, out of mind, right?  You would think so.  But time doesn’t stand still underground, especially if you have a lot of trees.  Over time, tree roots grow under and around the sprinkler pipes, sometimes choking them closed, other times pushing them to the surface, where they are more vulnerable to damage from freezing.  Sprinkler heads are also made of plastic and have internal parts which can be damaged if frozen.  In most cases, the damaged parts can’t be repaired, so the entire head has to be replaced.  I don’t know about you, but I’m seeing dollar signs.

Having your sprinkler system winterized is relatively inexpensive when compared to the cost of freeze repairs.  We charge between $75 and $85 for an average sized system; prices will vary depending on where you live.  You can do it yourself, but you will need to rent an air compressor designed for commercial use to do it properly.  By the time you add up the time spent and costs involved, it’s probably more practical to have a professional do it for you.  Compare the cost of repair, based upon our current pricing – a valve replacement runs around $125, sprinkler heads run anywhere from $60 to $100, and backflow devices are upwards of $200.  Add to this the $77 service call charge, and you’ll be shaking your head for not doing preventive maintenance.


Don’t forget your garden fountain – it needs winter maintenance, too.

Your sprinklers are an investment that reaps its rewards by saving your precious time, our precious water resources and your precious pennies.  So, when it comes to protecting your investment, an ounce of prevention really is worth a pound of cure.  And don’t forget your garden fountain – it needs to have the water drained as well to prevent cracking.  The professionals at Horizon Landscape will be happy to help you with all of your winter maintenance needs.

Call us anytime or email me with your preventative maintenance questions!