Washington is a state in the Pacific Northwest region of the United States. It is the 18th most populous state in the US with an estimated population of 7.6 million as of 2019. Washington is known for its diverse landscape, ranging from the Pacific Coast to the Cascade Mountains to the Columbia River Plateau. In Washington, changes to manufactured or mobile homes must be done under the regulations of the Washington State Building Code Council. Homeowners must obtain a permit from the local building department in order to make any alterations or modifications to their manufactured or mobile home. Changes must meet the applicable standards as prescribed by the Washington State Building Code Council and must be approved by the building department prior to being made. The types of changes to manufactured or mobile homes that require a permit in Washington include: — Structural alterations such as additions, decks, porches, stairs, and roof repairs. — Electrical alterations such as installing new wiring, outlets, and fixtures. — Plumbing alterations such as installing new pipes, fixtures, and drainage systems. — Heating and cooling alterations such as installing new HVAC systems and ducts. — Exterior alterations such as siding, windows, and doors. — Interior alterations such as drywall, flooring, and painting. — Other alterations such as installing solar panels or skirting.