In California, installers are necessary to have either a common contractors license or even a C-46 Solar Contractors License. This license handles installations for photovoltaic systems, solar water and space heating, and solar pool heating. Other certifications you must look out for, none of which might be legally necessary but https://californiasolarinstallation.wordpress.com/2025/11/19/livermores-trusted-solar-experts-for-home-business/