How do I winterize my sprinkler system before NB's first freeze?

You should winterize your sprinkler system in New Brunswick by late October at the latest, using compressed air to blow out all remaining water from the lines, valves, and heads before the ground freezes to frost depth. NB's frost depth reaches 1.2-1.5 metres, which means any water left in buried irrigation lines will freeze, expand, and crack pipes, fittings, and valve bodies. Repair costs from freeze damage typically run $300-1,000 or more, making the $75-150 cost of professional winterization one of the best investments in fall property maintenance.

The blow-out method is the industry standard in New Brunswick and the only reliable approach for our climate. Simply draining the system by opening valves relies on gravity and won't remove water trapped in low spots, elbows, or sprinkler heads. You need an air compressor capable of delivering 80-100 PSI and at least 20 CFM (cubic feet per minute) of volume. Most homeowner shop compressors don't have enough volume — they can reach the right pressure but can't sustain airflow long enough to clear the lines. Renting a commercial compressor costs $50-100 per day from NB equipment rental shops.

To blow out the system, start by shutting off the water supply to the irrigation system at the main shut-off valve, which is typically in the basement or mechanical room. Open the manual drain valve (if your system has one) and let water flow out. Then connect your air compressor to the blow-out fitting — this is usually a quick-connect or threaded port near the backflow preventer. Start at the zone farthest from the compressor and work your way closer. Run each zone for 2-3 minutes until only air (no water mist) comes out of the heads. Never exceed 80 PSI for PVC pipe systems or 50 PSI for polyethylene pipe — over-pressurizing can crack fittings or blow out seals.

After blowing out all zones, open the drain valves on the backflow preventer and leave them at a 45-degree angle for the winter. Remove any above-ground backflow prevention devices and store them indoors if possible. Shut off the controller and either disconnect it or set it to "rain" mode so it doesn't try to run cycles over winter.

Timing varies slightly across New Brunswick. Southern and coastal areas like Saint John and Moncton can usually wait until the last week of October, while inland areas around Fredericton should aim for mid-October, and northern NB around Bathurst and Campbellton should winterize by early October. A good rule of thumb is to have the system blown out at least two weeks before the average date of the ground freezing. Most NB irrigation companies book up quickly in October, so schedule your winterization appointment by early September to get your preferred date. If you prefer DIY, make sure you have the right compressor specifications — an undersized compressor that takes too long can overheat and damage itself while still leaving water in the lines.

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