In California, Installers are required to have possibly a normal contractors license or maybe a C-46 Solar Contractors License. This license covers installations for photovoltaic systems, solar drinking water and Area heating, and solar pool heating. Other certifications you must look out for, none of which can be lawfully required https://californiasolarcompany.car.blog/2025/08/23/california-solar-panels-energy-savings-with-expert-contractors/