Winterize Irrigation Systems Safely

Cross Connection Control Program

City of Coeur d’Alene water customers will soon start preparing their lawn and garden irrigation systems for the coming cold weather.

In our area, the most common practice is to use compressed air to blow out the leftover water in the irrigation piping.  

When performed correctly, this can be an efficient method to prevent expensive damage to irrigation systems caused by freezing.  If performed incorrectly, however, costly damage to backflow assemblies may occur.  You also run the risk of contaminating not only your water, but that of your neighbors. 

The following guidelines will help provide protection to you and other community members from irrigation system contamination:

1.  Make sure that the blow-off port where air is introduced into the irrigation system is downstream of your approved backflow assembly. Blow-off ports installed upstream of the backflow assembly may allow oil and contaminated air from the air compressor tank to be back pressured into your potable water service as well as the city water main.  High pressure air introduced upstream of the backflow assembly may also damage the internal components of the assembly, resulting in the assembly not properly protecting our drinking water supply, as well as costly repair/replacement of the assembly.     

2.  If your irrigation system is protected by a Pressure or Atmospheric Vacuum Breaker, it must be removed before the introduction of compressed air. These assemblies may be damaged if subjected to air from either upstream or downstream of the assembly.

3.  The City of Coeur d’Alene Municipal Code requires the backflow assembly to be installed with unions so it may be removed before the introduction of compressed air and stored inside for the winter. If the assembly was installed without unions and cannot be removed to prevent freezing, then it must be thoroughly drained.

4.  Remember to perform your required annual backflow assembly test at spring start-up, no later than July 1, to ensure the assembly is operating correctly.

If you have any questions, please feel free to contact Gary Alan Nolan in the City of Coeur d’Alene’s Water Department at 208-769-2298.