Residential Solar Permit Requirements

Washington's State Building Code sets requirements for the installation, inspection, maintenance and repair of solar photovoltaic (PV) energy systems. Local jurisdictions have the authority to issue building permits, or exempt systems from building permit requirements. Through an emergency rulemaking procedure, the State Building Council adopted revisions to the residential building code effective July 1, 2014. These amendments specify that installations meeting standard requirements are exempt from the roof covering specifications in the code, meaning they do not require an engineering report or stamped drawings. 

Jurisdictions still have authority over the permitting process for rooftop solar installations, but the rule change allows local governments to adopt "over-the-counter" permitting or exempt systems meeting the standard requirements from building permit requirements altogether. Northwest Solar Communities has developed a checklist template jurisdictions can choose to use for streamlining the permitting process, as well as recommendations for setting permit fees. 

The standard requirements for PV systems that are exempt from full engineering reports are:

• The system is designed for average windspeeds of the local area and installed per the manufacturer's specifications
• Ground snow load does not exceed 70 pounds per square foot
• The total dead load of the system does not exceed four pounds per square foot
• PV modules are not mounted higher than 18 inches above the roof
• Supports for the modules are installed to spread the dead load so that no point load exceeds 50 pounds.