The answer to 'downspouts water stains' is that water stains on downspouts are typically caused by mineral deposits, algae, or rust buildup. This can happen when water collects and drips down the downspout, leaving behind unsightly marks. Symptoms include discolored or streaked downspouts, which can detract from the appearance of your home's exterior.
The best solution is to regularly clean and maintain your downspouts. This can often be done as a DIY project, but for more severe staining or if the downspout is difficult to access, it's best to call in a professional roofing or gutter cleaning service. They can safely and effectively remove the stains using specialized cleaning solutions and techniques.