Safe for vinyl siding?

Worked well for mine but only time will tell if mold and mildew reappear.

Hi. Thank you for your question and interest in Concrobium products. The Concrobium House & Deck Wash is a general exterior cleaner, great for use on vinyl siding. It is meant for use on exterior surfaces to clean up and remove dirt, grime and surface mold and mildew staining. The Concrobium House & Deck Wash is not an antimicrobial and therefore there is no agent and/or ingredient in the solution to help the mold/mildew from reappearing. With that being said, on exterior surfaces to prevent mold from returning we recommend keeping up with the maintenance of your exterior surfaces by cleaning it often to remove any dirt or grime which is a food source for mold.