Solar panels are generally water-resistant, not waterproof. Two-in-one solar roofs can leave homeowners a bit skeptical at first glance, but they are just as much weatherproof as regular roofing materials. This guide covers waterproofing technologies, compatible roof types, installation steps, maintenance, and cost considerations. Let's find out more about the factors contributing to this difference and how to. Almost always, rooftop or ground-mounted solar arrays will have panels exposed to rainy, wet weather, meaning panels must be waterproof to keep producing power for many years. Most homeowners save around $60,000 over 25 years Because solar panels have been exposed to the elements for several.