In California, installers are necessary to have both a standard contractors license or maybe a C-46 Solar Contractors License. This license covers installations for photovoltaic systems, solar water and House heating, and solar pool heating. Other certifications you'll want to watch out for, none of which are legally demanded but https://solarpanelinstallersinconcord.blogspot.com/2025/07/what-makes-american-array-solar-best.html