Qualified Water Efficient Landscaper (QWEL) Practice Exam

Draining water from freezable parts of the irrigation system is essential to prevent damage caused by freezing temperatures. When water is left in the components, such as pipes, valves, and fittings, it can expand as it freezes. This expansion can lead to cracks and breaks in the system, which can be costly to repair and may result in inefficient irrigation when the system is restarted in warmer weather.

While turning off all controllers is beneficial for energy savings and preventing unnecessary operation during winter, it does not address the physical issue of water freezing within the system. Similarly, installing drip emitters or flushing the system may be useful for other purposes, but they do not directly prevent water from remaining in components that could be exposed to freezing conditions. Therefore, draining the freezable parts is the most crucial and effective practice for winterizing an irrigation system to ensure it functions properly when spring arrives.