It is possible to install a water softener outside, but it is not always recommended. Some water softener models are specifically designed for outdoor installation, but many are designed for indoor use only.
Installing a water softener outside can be more challenging due to potential exposure to extreme temperatures and weather conditions, which can damage the unit and its components. Outdoor installation requires a suitable and secure enclosure to protect the unit from the elements, such as direct sunlight, rain, snow, and extreme temperatures. If not protected properly, the water softener could be damaged and may not function properly.
Another important factor to consider is the availability of power and water supply. Water softener needs a continuous supply of water and electricity to function, so it's important to make sure that there is a nearby water supply line and an electrical outlet to plug in the unit.
If you are considering installing a water softener outside, it is best to contact the manufacturer or a professional plumber to ensure proper installation and to avoid any potential issues. They will be able to advise you on the best location and method of installation, and whether the specific model you are considering is suitable for outdoor use.