Solar power plants do not require much maintenance. As the panels do not contain rotating or otherwise moving parts, the only regular maintenance required is to check that the solar modules are clean, free of dust or pollen, and not covered with leaves or snow. In practice it is rarely necessary. If the angle of inclination is greater than 10 degrees to the surface, the panels will be cleaned by rain. If solar panels are installed next to a building that is subject to a maintenance service agreement, the solar power plant is also included in the maintenance.