I want to build a website that will estimate the cost of going solar. Are building permits for installing solar in the united states done by County, City, or State? or does it vary?
In the U.S., building permits are generally administered and controlled by the county. Contact your local county planning office to get more information on what their requirements are for solar. If you are really lucky, you may even find you are eligible for a rebate of some sort for going "green."