What likely causes a sprinkler head to mist?

When a sprinkler head mists, it is commonly due to excessive water pressure. When the pressure at the sprinkler head is too high, water is forced out with such velocity that instead of forming a solid stream, it breaks into smaller droplets or mist. This phenomenon can lead to a fine spray that does not effectively reach the intended area for irrigation, resulting in reduced efficiency and possibly uneven watering.

While damaged sprinkler heads can also cause issues with water distribution, they typically lead to leaks or uneven spraying rather than misting specifically. Blockages in the water supply can affect water flow, but they would more likely cause reduced output rather than creating mist. Similarly, low water quality, while it may lead to clogging or other problems, doesn't directly cause the misting effect associated with high-pressure situations. Therefore, high pressure is the primary factor that contributes to the misting of a sprinkler head.